Not sure, but I wonder if this is a clip of Dave Johns on Radio Atlantis? He was the station representative in London and had a one hour programme on 30th August 1974. Quite a few of the air checks are from that date including one from Ray Warner who followed Dave Johns.
From Monitor magazine number 7.
The station's last two days can best be summarised by giving a complete programme run-down: (30th) 06.00-09.00 "Snap, Crackle & Pop" Dave Owen, 09.00-11.00 "The Rogers' Ranch" Dave Rogers, 11.00-13.00 "The Nightmare Affair" Scott Mitchell & Gabby Hernandez Omilado (a repeat of an earlier broadcast. The characters of Scott and Gabby were both impersonated by ex-Radio City and Radio 270 DJ Leon Tipler), 13.00-15,00 "Luncheon Voucher" Andy Anderson, 15.00-16.00 Dave Johns (his 1st and only show, it was recorded in London where Dave acted as station representative), 16.00-17.00 Ray Warner, 17.00-19.00 Steve England, 19.00-21.00 "Blast-off" John Harding, 21.00-24.00 Derek Jones, 24.00-03.00 Debbie England,