I am new to this web site but I may have a bit more info for you.
I have updated the wikipedia entry for Heston.
more details here :-
I updated a section on Woodason model makers.
They were based at the site making models initially for WWII military then for film making after the war.
More details here :-
unfortunately I cannot find any info after WWII.
The only info I found was that racing commenced on there perimeter track around the aerodrome but I cannot verify dates etc.
If anyone else has info then please advise.