Yep...the cannon has now lost the end "flash" (only since removal of the IR system), the cannon recoil ONLY works with the Tx left stick UP (not synchronised with the tank recoil / cannon sound).
I've deliberately disabled the very annoying mg firing that accompanied the cannon elevation, but need to somehow connect this to the main mg to fire simultaneously.

If I recall correctly (I'm losing it!!) the black wire was connected to the microswitch alongside the cannon....but not sure. Sorry. Need to have yet another mooch inside the turret, trouble is that each time one of the plastic hand-holds / attachments gets broken-off when I do this, they are so flimsy, but hey, not to worry, they will be replaced with wire versions!!

Oh and one final thing...the button / wires that morph this into the Tamiya Leo 2A6 seems to be missing. I'm sure I ordered it when I bought this....!!!