Reasonable questions. Are you questioning the ability of a loaded Martlet to turn inside a Seafire? I have no idea, as I said it surprised me. I would have guessed the Martlet would outroll a Spitfire but not outturn it.I like the bit about the stubby little wings on the Martlet, which were 38ft in span or 1ft 2in longer than the Spitfire's wings.
If they were working up with planes that would be used in combat then the martlet model can probably be trimmed down to Martlet IV.
This is because the Martlet II and III (100 and 30 built respectively) would have been almost two years old in 1943.
The Martlet IV started deliveries in the summer of 1942 and 220 were built making a much more likely plane to being used in early 1943.
I would also note that the Martlet IV used a Aright R-1820 engine that was several hundred pounds lighter than the R-1830 used in the F4F-4.
One also wonders about the ammo load on such training flights. A 6 gun Martlet would be carrying 432lbs of ammo if it was carrying ammo.