Question: What performer recorded a live album at the broadcast studios that employed Allan Powell?

full_context: Document 1: Allan Quartermaine: Allan Stephen Quartermaine was born in London on 9 November 1888 and, after attending Highgate School, was awarded a Bachelor of Science degree in engineering at University College London, where he was a Chadwick Scholar and later a Fellow. He served as a commissioned officer in the Royal Engineers during the First World War and was awarded the Military Cross for gallantry as a Temporary Captain. Quartermaine was promoted to Acting Major on 24 May 1919, a rank he relinquished on 15 June 1919. Between the wars he worked for Hertfordshire County Council Surveyor’s Department, Teesside Bridge and Engineering and for Great Western Railway, where he became Assistant Chief Engineer, but he remained liable for recall to the British Army as he was a Captain of the Royal Engineers (Transportation) in the Supplementary Reserve of Officers, being promoted to Major in that unit on 19 November 1924. Quartermaine resigned from the Supplementary Reserve on 1 January 1926, transferring immediately to the Regular Army Reserve of Officers whilst retaining his rank and association with the Royal Engineers. He reached the age limit (50) for recall to the British Army on 9 November 1938 and as of that date ceased to be a member of the British Army reserves. He was Director-General, Aircraft Production Factories in 1940 and Chief Engineer, Great Western Railway and Western Region of British Railways from 1940–51.
Document 2: BBC: The British Broadcasting Corporation came into existence on 1 January 1927, and Reith -- newly knighted -- was appointed its first Director General. To represent its purpose and (stated) values, the new corporation adopted the coat of arms, including the motto ``Nation shall speak peace unto Nation ''.
Document 3: BBC Television: After a series of test transmissions and special broadcasts that began in August 1936, the BBC Television Service officially launched on 2 November 1936 from a converted wing of Alexandra Palace in London. ``Ally Pally ''housed two studios, various scenery stores, make - up areas, dressing rooms, offices, and the transmitter itself, which then broadcast on the VHF band. BBC television initially used two systems on alternate weeks: the 240 - line Baird intermediate film system and the 405 - line Marconi - EMI system. The use of both formats made the BBC's service the world's first regular high - definition television service; it broadcast from Monday to Saturday between 15: 00 and 16: 00, and 21: 00 and 22: 00. The first programme broadcast -- and thus the first ever, on a dedicated TV channel -- was`` Opening of the BBC Television Service'' at 15: 00. The first major outside broadcast was the coronation of King George VI and Queen Elizabeth in May 1937.
Document 4: Allan Powell: Sir George Allan Powell GBE (1 February 1876 – 24 January 1948) was Chairman of the BBC Board of Governors between 1939-46.
Document 5: Live at the BBC (Fleetwood Mac album): Live at the BBC is a double compact disc compilation album by British blues rock band Fleetwood Mac, recorded at various BBC radio sessions between 1967 and 1971. It contains many tracks by Fleetwood Mac which are otherwise unavailable.
Document 6: Live at Leeds: Live at Leeds is the first live album by the English rock band The Who. It was recorded at the University Refectory, University of Leeds on 14 February 1970, and is the only live album that was released while the group were still actively recording and performing with their best known line - up of Roger Daltrey, Pete Townshend, John Entwistle and Keith Moon. Initially released in the United States on 16 May, by Decca and MCA and the United Kingdom on 23 May, by Track and Polydor, the album has been reissued on several occasions and in several different formats. Since its release, Live at Leeds has been cited by several music critics as the best live rock recording of all time.
Document 7: BBC Sessions (Led Zeppelin album): BBC Sessions is a compilation album featuring studio sessions and a live concert recorded by English rock group Led Zeppelin for the BBC. It was released on 11 November 1997, by Atlantic Records. Disc one consists of material from four different 1969 BBC sessions. Disc two contains most of the 1 April 1971 concert from the Paris Theatre in London. Disc three was only included in a limited run of album releases and features rare interviews from 1969, 1976/1977, and 1990.
Document 8: BBC Sessions (Cocteau Twins album): BBC Sessions is an album of BBC studio recordings by the band Cocteau Twins released in 1999 by Bella Union in the UK and Rykodisc in the US. The album spanned the band's career from the early 1980s through the 1990s. Much of the first disk was taken from a series of early 1980s Peel sessions. The second disk contained several tracks recorded during the group's performance on the 1980s Radio 1 series "Saturday Live". The compilation peaked at No. 87 on the UK Albums Chart.
Document 9: George Powell-Shedden: George Ffolliott Powell-Shedden, (1 April 1916 – 31 October 1994) was a Royal Air Force pilot who flew during the Battle of Britain and later went on to operational commands. He was also an Olympic bobsledder who competed for Britain in the late 1940s.
Document 10: Albert Powell: Albert "Bertie" William Powell (18 July 1873 – 11 September 1948) was a South African sportsman who played both international cricket and rugby union for South Africa.
Document 11: Live at the BBC (Sandy Denny album): Live at the BBC is a four disc compilation of British folk singer songwriter Sandy Denny's BBC sessions from 1966 to 1973 and contains almost all her solo work for the corporation. Disc 4 of the set is a DVD of Denny performing three songs on the music programme "One in ten" in 1971: the only surviving solo footage of her. This compilation superseded the earlier one-disc set issued on the Strange Fruit label in 1997 that due to rights issues was withdrawn on the day of release thereby creating a highly collectable disc up until the release of this comprehensive set.
Document 12: Now and Live: Now & Live is a double CD compilation-like album released in 1997 by Paul Rodgers of Free and Bad Company fame. In fact, it is a re-release of the studio album "Now" including a disc of live material recorded in 1995 and issued on the album "".
Document 13: George VI: In 1940, Winston Churchill replaced Neville Chamberlain as Prime Minister, though personally George would have preferred to appoint Lord Halifax. After the King's initial dismay over Churchill's appointment of Lord Beaverbrook to the Cabinet, he and Churchill developed "the closest personal relationship in modern British history between a monarch and a Prime Minister". Every Tuesday for four and a half years from September 1940, the two men met privately for lunch to discuss the war in secret and with frankness.
Document 14: BBC Television: Mechanically scanned, 30-line television broadcasts by John Logie Baird began in 1929, using the BBC transmitter in London, and by 1930 a regular schedule of programmes was transmitted from the BBC antenna in Brookmans Park. Television production was switched from Baird's company to what is now known as BBC One on 2 August 1932, and continued until September 1935. Regularly scheduled electronically scanned television began from Alexandra Palace in London on 2 November 1936, to just a few hundred viewers in the immediate area. The first programme broadcast – and thus the first ever, on a dedicated TV channel – was "Opening of the BBC Television Service" at 15:00. The first major outside broadcast was the coronation of King George VI and Queen Elizabeth in May 1937. The service was reaching an estimated 25,000–40,000 homes before the outbreak of World War II which caused the service to be suspended in September 1939. The VHF broadcasts would have provided an ideal radio beacon for German bombers homing in on London, and the engineers and technicians of the service would be needed for the war effort, in particular the radar programme.
Document 15: Live on Blueberry Hill: The audience recording is one of the first Led Zeppelin bootlegs, and one of the first ever rock and roll bootlegs. It was released on the Blimp label. The album was reissued on the Trademark of Quality label and shipped to England. The album sold so many copies that many fans thought it was a legal release. The sleeve notes describe it as "One hundred and six minutes and fifty three seconds of pure alive rock."
ground_truth: Fleetwood Mac
sub_queries: Allan Powell >> employer Answer: BBC
Live at the BBC >> performer Answer: Fleetwood Mac