Question: Robert Cecil Dawkins was a senior office in the Royal Air Force with a rank immediately below what other rank?

Context paragraphs:
List of Royal Australian Air Force air marshals: The following is a list of Australians who have attained air marshal rank within the Royal Australian Air Force (RAAF); that is, service personnel who have held the rank of air chief marshal (four-star rank), air marshal (three-star rank) or air vice marshal (two-star rank).  The Royal Australian Air Force was established in 1921 as a separate branch of the Australian military forces.  The service was modelled after the Royal Air Force—formed three years earlier—and adopted the same ranking system.  Richard Williams, regarded as the "father" of the Royal Australian Air Force, was the service's first member to obtain air-officer rank on being promoted to air commodore (one-star rank) in 1927; he went on to become the first air vice marshal (1935) and air marshal (1940).  In 1965, Sir Frederick Scherger became the first officer to be advanced to air chief marshal, one of only four members of the Royal Australian Air Force to obtain this rank as of June 2014.  A further nineteen individuals have reached air marshal in the RAAF and 126 air vice marshal; seven officers have retired with the honorary rank of air vice marshal.

Michael Beetham: Marshal of the Royal Air Force Sir Michael James Beetham, (17 May 1923 – 24 October 2015) was a Second World War bomber pilot and a high-ranking commander in the Royal Air Force from the 1960s to the 1980s.  As Chief of the Air Staff during the Falklands War he was involved in the decision to send the Task Force to the South Atlantic.  At the time of his death Beetham was one of only six people holding his service's most senior rank and, excluding Prince Philip's honorary rank, and had the longest time in rank, making him the senior Marshal of the Royal Air Force.

Robert Cecil Dawkins: Group Captain Robert Cecil Dawkins CBE (1903-1985) was a senior officer in the Royal Air Force.  In September 1951 he was made CBE for services in Malaya, principally for operational achievements while he was in command of the R.A.F. station at Tengah.  In 1951 he was made station commander at R.A.F. Hendon until his retirement in 1955.

Field marshal (United Kingdom): Field Marshal has been the highest rank in the British Army since 1736.  A five-star rank with NATO code OF-10, it is equivalent to an Admiral of the Fleet in the Royal Navy or a Marshal of the Royal Air Force in the Royal Air Force (RAF).  A Field Marshal's insignia consists of two crossed batons surrounded by yellow leaves below St Edward's Crown.  Like Marshals of the RAF and Admirals of the Fleet, Field Marshals traditionally remain officers for life, though on half-pay when not in an appointment.  The rank has been used sporadically throughout its history and was vacant during parts of the 18th and 19th centuries (when all former holders of the rank were deceased).  After the Second World War, it became standard practice to appoint the Chief of the Imperial General Staff (later renamed Chief of the General Staff) to the rank on his last day in the post.  Army officers occupying the post of Chief of the Defence Staff, the professional head of all the British Armed Forces, were usually promoted to the rank upon their appointment.

Air Force ranks and insignia of India: The Indian Air Force's rank structure is based on that of the Royal Air Force.  The highest rank attainable in the Indian Air Force is Marshal of the Indian Air Force, conferred by the President of India after exceptional service during wartime.  MIAF Arjan Singh is the only officer to have achieved this rank.  The head of the Indian Air Force is the Chief of the Air Staff, who holds the rank of Air Chief Marshal.  The current Chief of the Air Staff is Air Chief Marshal Birender Singh Dhanoa, appointed on 31 December 2016, following the retirement of Air Chief Marshal Arup Raha.

Group captain: Group Captain, is a senior commissioned rank in many air forces.  Group Captain has a NATO rank code of OF-5, meaning that it ranks above Wing commander, immediately below Air Commodore and is the equivalent of the naval rank of Captain and the rank of Colonel in other services.

Royal Air Force Music Services: Royal Air Force Music Services is the organization which provides military musical support to the Royal Air Force.  Based at RAF Northolt (previously at RAF Uxbridge) and RAF Cranwell, it forms the central administration of one hundred and seventy musicians divided between the Central Band of the Royal Air Force, The Band of the Royal Air Force College, The Band of the Royal Air Force Regiment and Headquarters Music Services.  These main military bands contain within their ranks the Royal Air Force Squadronnaires, Royal Air Force Swing Wing, Royal Air Force Shades of Blue, and The Salon Orchestra of the Central Band of the Royal Air Force.

Marshal of the Royal Australian Air Force: Marshal of the Royal Australian Air Force (MRAAF) is the highest rank of the Royal Australian Air Force and was created as a direct equivalent of the British Royal Air Force rank of Marshal of the Royal Air Force.  It is considered a five-star rank.

List of Marshals of the Royal Thai Air Force: Chom Phon Akat (Thai: จอมพลอากาศ ) or Marshal of the Royal Thai Air Force is a 5-star rank and the most senior rank in the Royal Thai Air Force.  It is equivalent to a Field Marshal (or "Chom Phon") in the Royal Thai Army and an Admiral of the Fleet (or "Chom Phon Ruea") in the Royal Thai Navy.  The rank of Marshal of the RTAF is also equivalent to the British rank of Marshal of the Royal Air Force.

Marshal of the Royal Air Force: Marshal of the Royal Air Force (MRAF) is the highest rank in the British Royal Air Force (RAF).  In peacetime it was granted to RAF officers in the appointment of Chief of the Defence Staff (CDS), and to retired Chiefs of the Air Staff (CAS), who were promoted to it on their last day of service.  While surviving marshals of the RAF retain the rank for life, the highest rank to which officers on active service are promoted is now air chief marshal.  Although general promotions to Marshal of the Royal Air Force have been discontinued since the British defence cuts of the 1990s, further promotions to the rank may still be made in wartime, for members of the Royal Family and certain very senior RAF air officers in peacetime at the discretion of the monarch; all such promotions in peacetime are only honorary, however.  In 2012, Charles, Prince of Wales was promoted to the rank while in 2014 Lord Stirrup, who had served as Chief of the Air Staff and Chief of the Defence Staff for over seven years, was also promoted.

Supporting paragraphs: Robert Cecil Dawkins Group captain
Answer: Air Commodore