Question: Where is the base of one of the three main British intelligence agencies?

full_context: Document 1: Security agency: A security agency is a governmental organization which conducts intelligence activities for the internal security of a nation. They are the domestic cousins of foreign intelligence agencies, and typically conduct counterintelligence to thwart other countries' foreign intelligence efforts. For example, the United States Federal Bureau of Investigation (FBI) is the internal intelligence, security and law enforcement agency, while the Central Intelligence Agency (CIA) is an external intelligence service, which deals primarily with intelligence collection overseas. A similar relationship exists in Britain between MI5 and MI6.
Document 2: Defence Strategic Policy and Intelligence Group: The Defence Strategic Policy and Intelligence Group (SP&I) of the Australian Government Department of Defence is responsible for defence diplomacy, strategic policy, international security, and military intelligence coordination and advice to the Prime Minister of Australia, Minister for Defence, Secretary of the Department of Defence, and Chief of the Defence Force. The Defence Strategic Policy and Intelligence Group is led by the Deputy Secretary for Strategic Policy and Intelligence and comprises four policy divisions and three intelligence agencies, which are the Australian Defence Organisation members of the Australian Intelligence Community.
Document 3: Private Secretary to the Sovereign: The Private Secretary to the Sovereign is the senior operational member of the Royal Household of the Sovereign of the United Kingdom (as distinct from the Great Officers of the Household). The Private Secretary is the principal channel of communication between the monarch and the governments in each of the Commonwealth realms. They also have responsibility for the official programme and correspondence of the Sovereign. Through these roles the position wields considerable influence.
Document 4: Susan M. Gordon: Susan M. Gordon is an American government official who currently serves as Principal Deputy Director of National Intelligence. Prior to assuming her current role, she was the Deputy Director of the National Geospatial-Intelligence Agency (NGA), having assumed the position on January 1, 2015. Before joining the NGA, she served as director of the CIA's Information Operations Center and senior cyber adviser to the Director of the Central Intelligence Agency. Gordon worked for the Central Intelligence Agency for over 25 years.
Document 5: Israel's Secret Wars: It explores the role of secret intelligence and covert activities in the Zionist movement before independence and explore the operational and political histories all three major Israeli intelligence agencies Aman (military intelligence), Mossad (foreign intelligence and covert operations) and Shin Bet (internal security).
Document 6: Bangladeshi intelligence community: The Bangladesh intelligence community is a group of several intelligence agencies charged with carrying out intelligence gathering activities considered necessary for the conduct of foreign relations and national security of Bangladesh including other functions vital for the national security of Bangladesh. Member organizations of the Bangladesh intelligence community include military intelligence of Bangladesh Army, Navy, Air Force, National Police and civilian intelligence and analysis offices within executive ministries. The I.C. is headed by a Director heading each Intelligence agency, who reports to the Prime Minister of the Bangladesh.The organisation and structure of the modern Bangladesh intelligence community has developed its structures from agencies that continued to function after Independence from Pakistan. Bangladesh intelligence agencies today are the National Security Intelligence, the Special Branch, Army Intelligence, Air Force Intelligence, Naval Intelligence and the Directorate General of Forces Intelligence (DGFI). During the 1971 Bangladesh Independence War, the Bangladesh Forces in the 11 BDF Sectors also developed an intelligence network within its organisation of guerrilla combat teams that provided the sectors with essential local intelligence. However, the intelligence agency personnel have been and still continues to be recruited and trained from within the particular agency. Among their varied responsibilities, the members of the Community collect and produce foreign and domestic intelligence, contribute to military planning, and perform espionage.
Document 7: MI5: The Security Service, also MI5 (Military Intelligence, Section 5), is the United Kingdom's domestic counter-intelligence and security agency and is part of its intelligence machinery alongside the Secret Intelligence Service (MI6), Government Communications Headquarters (GCHQ) and Defence Intelligence (DI). MI5 is directed by the Joint Intelligence Committee (JIC), and the service is bound by the Security Service Act 1989. The service is directed to protect British parliamentary democracy and economic interests, and counter terrorism and espionage within the UK.
Document 8: Secret service: A secret service is a government agency, intelligence agency, or the activities of a government agency, concerned with the gathering of intelligence data. The tasks and powers of a secret service can vary greatly from one country to another. For instance, a country may establish a secret service which has some policing powers (such as surveillance) but not others. The powers and duties of a government organization may be partly secret and partly not. The organization may be said to operate openly at home and secretly abroad, or vice versa. Secret police and intelligence agencies can usually be considered secret services.
Document 9: Secret police: The term secret police or covert police force refers to intelligence services or police and law enforcement agencies which engage in covert, domestic law enforcement, intelligence, and counter-intelligence operations. The level of oversight with which they are governed varies by country and political system. Secret police organizations are often used by totalitarian states to protect the political power of an individual dictator or an authoritarian political regime by means of systematic engagement in extrajudicial activities. Secret police organisations are often utilised for the purposes of policing the activities of dissidents, and weakening opposition organisations.
Document 10: Great Offices of State: The Great Offices of State in the United Kingdom are the four most senior and prestigious posts in the British government. They are the Prime Minister, Chancellor of the Exchequer, Foreign Secretary and Home Secretary. According to convention, when the Prime Minister names his or her Cabinet, either after a general election or a mid-term reshuffle, the first Cabinet ministers to be announced are the Chancellor, the Foreign Secretary and the Home Secretary.
Document 11: Cyber Security Agency (Singapore): The Cyber Security Agency of Singapore (CSA) is a Singaporean government agency under the Prime Minister's Office that provides centralised oversight of national cyber security functions, and works with public and private sector leads to protect Singapore’s critical services, such as those in the energy and banking sectors. Formed on 1 April 2015, the agency also engages with various industries and stakeholders to heighten cyber security awareness as well as to ensure the development of Singapore’s cyber security. It is headed by Ministry of Defence's deputy secretary of technology David Koh. The Minister-in-charge is Yaacob Ibrahim of the Ministry of Communications and Information.
Document 12: Government Communications Headquarters: The Government Communications Headquarters (GCHQ) is an intelligence and security organisation responsible for providing signals intelligence (SIGINT) and information assurance to the government and armed forces of the United Kingdom. Based in "The Doughnut" in the suburbs of Cheltenham, GCHQ is the responsibility of the country's Secretary of State for Foreign and Commonwealth Affairs, but it is not a part of the Foreign Office and its director ranks as a Permanent Secretary.
Document 13: Directorate of Military Intelligence (Ireland): The Directorate of Military Intelligence ("G2") (Irish: "Stiúrthóireacht na Faisnéise" ) is the military intelligence branch of the Defence Forces, the Irish armed forces, and the national intelligence service of Ireland. The organisation has responsibility for the safety and security of the Irish Defence Forces, its personnel, and supporting the national security of Ireland. The Directorate operates domestic and foreign intelligence sections, providing intelligence to the Government of Ireland concerning threats to the security of the state and the national interest from internal and external sources.
Document 14: British intelligence agencies: The Government of the United Kingdom maintains intelligence agencies within several different government departments. The agencies are responsible for collecting and producing foreign and domestic intelligence, providing military intelligence, performing espionage and counter-espionage. Their intelligence assessments contribute to the conduct of the foreign relations of the United Kingdom, maintaining the national security of the United Kingdom, military planning and law enforcement in the United Kingdom. The three main agencies are the Secret Intelligence Service (MI6), the Security Service (MI5), and the Government Communications Headquarters (GCHQ).
Document 15: General Intelligence Directorate (Egypt): The General Intelligence Directorate (Arabic: جهاز المخابرات العامة‎ ‎ "Gihaz El Mukhabarat El ‘Amma" ), often referred to as the Mukhabarat (Egyptian Arabic: المخابرات‎ ‎ "El Mukhabarat" ) is an Egyptian intelligence agency responsible for providing national security intelligence, both domestically and transnationally, with a counter-terrorism focus. The GID is part of the Egyptian intelligence community, together with the Office of Military Intelligence Services and Reconnaissance (Egyptian Arabic: إدارة المخابرات الحربية والاستطلاع‎ ‎ "Idarat El Mukhabarat El Ḥarbiya Wel Istitlaʾ" ) and National Security Agency (Egyptian Arabic: قطاع الأمن الوطني‎ ‎ "Ketaʿ El Amn El Watani" ).
ground_truth: Cheltenham