I've just now had a relook at both websites and Dever does give some clues about what size blues they are stocking but has not mentioned the size of rainbows that have been stocked.
Avington doesn't really give any size but refers to the fishing reports which mention the "doubles".
Incidentally I might have to ammend my earlier figure of 36 "doubles" stocked in a year to 33. This is an extract from the December report......
"The fishery was fairly quiet this month mainly due to the cold weather........
The large double figure fish remained elusive this month, mainly due to the adverse stalking conditions."
Lechlade have some champion fish from memory but the lake is not as clear as Dever, Avington and Avon Springs.