My father is a 96 years old survivor of Biggin Hill in Sept 1940. He wasn't a pilot, he was an LAC who helped keep the aircraft serviceable, refuelled and re armed, even if the airfield was under attack. His billet was a tent on the perimeter of the airfield.
When I found out this event was planned I sent a request for him to be able to attend as a veteran of those days. I received a reply saying his name was added to a list and further correspondence would follow. I guess they didn't need any engineers at the event because there was never any follow up despite another polite enquiry from me. Very disappointing.
It is very commendable that there is recognition of the bravery of those involved in the battle of 1940, but as others have suggested on here already, there are more stories to tell than just the RAF fighter pilots.