Further to the discussion in the chatbox following Geoffrey Wellum's passing, it appears my information was not correct - The surviving pilots who fought during the summer of 1940 are;
Flt Lt William Terence Clark DFM - 219 Squadron - Blenheims
Wing Co John Francis Durham Elkington - 1 Squadron - Hurricanes
Wing Co Paul Caswell Farnes DFM - 501 Squadron - Hurricanes
Squadron Leader J. S. Hart - 602 (Canadian), 54, 81 and 602 Squadrons
F/O John Allman Hemingway DFC - 86 Squadron - Hurricanes
Flt Lt William Robert Kent Hughes DFC, AE - 23 Squadron - Blenheims
Flt Lt Ronald MacKay - 234 Squadron - Spitfires (Not verified - if he is still alive he is 108!)
Flt Lt Archibald McInnes - 601 & 238 Squadrons - Hurricanes
Flt Lt Maurice Hewlett Mounsdon - 56 Squadron - Hurricanes
Thought this might be of interest.