1975? Me too.
Cam "K" because it was the one that worked after cams A to J had been rejected.
Weren't we lucky not to have had cam "A"?
Necessary because the fore and aft stick travel was insufficient to cope with the static stability, Mach trim and CG shift in the two-seater (one or two pilots) after the modification from the single seat Midge to the two seat Gnat. It meant that if you trimmed properly the stick was always somewhere in the mid position at most speeds and that you could always get sufficient back stick to "round-out"
, unless you got the unlock wrong!
I bet we've all at some time flopped it onto the runway with the stick right back and hard over one way or the other to cope with the cross-wind.
Always a most demanding and potentially unforgiving advanced trainer.