My first airshow was Biggin Hill too, but 1982!
I was at Abingdon in 1990 as well, but only just. Went there on a coach tour, got caught in the huge traffic jam, missed the big flypast, and got to the airfield about just under 2 hours before we had to leave again 😡 I think it took us about three hours to just get off the airfield on the way back.
I have some really nice pix from the static though………………..Anyone like to see them??