In the sixties and seventies the fire practice dump was on the south (River Taw ) side, towards the eastern end. Over the years they got through at least two Hunters, a Meteor F8, a Javelin, a Skeeter(!) , another Hunter F.4 from the ATC Sqn at Devizes, and a Canberra B(I)8. The wreck of Hunter F.6 XF420 was dumped near the old station pig farm on the western boundary prior to closure of the airfield to fixed wing ops in 1974.
In Chivenor’s second period of activity, from 1980, the dump was further to the west, not far from the old firing butts, and I don’t believe that any burning took place, just Battle Damage Repair patching. They used a Hunter T.7 fuselage, a Canberra TT.18, and the aforementioned Jet Provost. There was also a Canberra nose section near some old pillboxes at the western end for a while.
Hope this helps.