Correct, the Monday TriStar and all of the British Airtours LBA flying in 1985 was for Intasun, with Lancaster and Carousel listed as additional charterers. Thomson also had a Britannia 767 on Leeds-Palma that year.
Interesting to know the background on G-AVRN, thanks for that - makes absolute sense once you know! I also never knew of the differences with G-BADP/BADR. [Sir Arthur Whitten Brown and Robert Falcon Scott!]