The carcass was actually found in August of 1953 at Girvan, in West Scotland, and turned out to be a dead basking shark, as many "sea monster carcasses" have.
Yesterday, while doing some research for a new book (more on it later!), I came upon a newspaper article on this certain carcass from the September 9, 1953 edition of the Sydney Morning Herald. The paper showed a photo of the carcass with the headline of "Scotland's New Sea Monster." Underneath it read:
"The decomposed remains of a sea monster which was washed ashore at Girvan, West Scotland, on August 15. The monster was 30ft long, with a 4ft neck, four stumpy legs and a 12ft tail. Inhabitants of Girvan said they had sighted the monster's mate swimming near the coast, and they spent days hunting it. The townspeople, objecting to the stench of the carcass, poured oil on it and set it alight."
An interesting tidbit, though we know it wasn't really a monster!
The only curious thing in the article was the mention of "the monster's mate." It is not stated if this was before or after the carcass was found. It could have been a basking shark, possibly the one found, or it could have been a second one.