Broad Left is a coalition of leftist members, usually involving independents, members of the Labour Party (UK) (although some people deny that the Labour Party still constitute as "broad left"), and members of organised revolutionary leftist movements within a trade union, or members of a political party that appeals to a wide range of leftist ideologies, such as Left Unity (UK).
Left Unity is a left-wing political party in the United Kingdom, which was founded in 2013 when film director Ken Loach appealed for a new party to replace the Labour Party (which, he claimed, failed to oppose austerity and had shifted towards neoliberalism).
Helen Mary Caldicott (born 7 August 1938) is an Australian physician, author, and anti-nuclear advocate who has founded several associations dedicated to opposing the use of nuclear power, depleted uranium munitions, nuclear weapons, nuclear weapons proliferation, and military action in general.
Katharine Jane "Kate" Hudson (born 1958) is a British left wing political activist and academic who is the General Secretary of the Campaign for Nuclear Disarmament (CND) and Media Officer of Left Unity.
 She served as Chair of CND from 2003 to 2010.
 She has been an officer of the Stop the War Coalition since 2002.
Left Unity is a not-for-profit incorporated association established in South Australia for the purpose of uniting the state's political left and supporting progressive social and environmental activism.
 It was formed in 2010 and was later incorporated.
 By mid-2012, Left Unity had coordinated community pickets against the South Australian Defence Industry Exhibition (DIE), engaged in solidarity actions during a Lilydale industrial dispute, marched at May Day rallies and organised public forums on various topics.
 Topics represented at public forums have included: carbon tax, occupational health and safety, education and neoliberalism and worker cooperatives. Left Unity hosted Afghan dissident and feminist Malalai Joya in 2011 and anti-nuclear activist Helen Caldicott in 2012.
Unity (Hungarian: "Összefogás" ), also called: Left unity (Hungarian: "Baloldali összefogás") was the informal name of a short-lived political alliance in Hungary of five political parties formed for contesting the 2014 Hungarian parliamentary election.
Workers Left Unity – Iran (Persian: اتحاد چپ کارگری‎ ‎ ) is an Iranian far left political party in exile.
Left Grouping of the Valencian Country (in Catalan: "Agrupament d'Esquerra del País Valencià") was a political group created in 1982 out of a nationalist splinter-group of the Communist Party of the Valencian Country (PCPV), the 'possibilist' sector of the Socialist Party of National Liberation of the Catalan Countries (PSAN) and independent leftwing nationalists.
 AEPV was registered as a political party.
 Soon after its foundation AEPV initiated cooperation with the Nationalist Party of the Valencian Country (PNPV) and the Left Unity of the Valencian Country (UEPV), with whom AEPV founded the coalition Valencian People's Union (UPV).
Lieutenant Colonel Sir Charles George McDonald {'1': ", '2': ", '3': 'KCMG, KBE, KCSG, FRCP, FRACP', '4': "} (25 March 1892 – 23 April 1970) was an Australian physician, army officer and academic.
 He was noted for his work as a physician in the field of Tuberculosis and during the Second World War served in Greece and Palestine as a lieutenant colonel in the Australian Imperial Force.
 On his return to Australia, he served in various academic positions culminating in his appointment as Chancellor of the University of Sydney in 1964.
New Galician Left (NEG, "Nova Esquerda Galega" in Galician language) is a Galician political organization.
 It was formed in 2013 with former members of the Galician Left Unity (UEG) and the entire membership of the New Socialist Left (NES), both groups integrated in Anova-Nationalist Brotherhood since its foundation.
 This organization, formed through the merger of the two small parties, was also joined by about twenty ex-militants of the Galician Socialist Party (PSdeG).

Question: Who did Left Unity host that is an Australian physician?
Answer: Helen Caldicott