AUSTER AOP
I believe that the “scrapyard” you refer to is in fact a car dealership,Holders of Congresbury. It is still in buisness as a Seat dealer but used to be a BL Dealer back in the seventies.
I remember well the aircraft to which you refer as they were for sale literally on the forecourt as they were stored by the side of the showroom at, priced at about £1200 each. At the time, which must have been 1972/3, i was in the ATC and cycled down to look at them a round trip of 10 miles or so. They all had their wings removed and believe you are correct in saying that they came from Toogoods in bedminster bristol.
When they left i cant remember. im sure there was coverage in one of the aircraft magazines of the time ,Air Pictorial or maybe the story was covered by the local newspaper the Clevedon Mercury.
Hope this helps i might be able to narrow the date a bit further if you want and the registrations maybe.
Simon Thompson