Won't be the TDC sensor. It really doesn't know (or care) which cylinders are firing.

Well, whatever I've done, the mixture seems to be ok now and the misfire is gone. Still seems to be a bit rough at idle though and the rev bouncing is back - not all the time and clears if you switch the engine off and restart it.

Worthwhile swapping out -- or removing and good cleaning -- the throttle body. Hunting idle is usually idle air control problem.