Yep I'll take off the rocker cover (and loosen off the engine mounts a fraction). I left the rocker cover on when installing the motor, it was tight but I got there in the end

The headers have a flange so disconnecting the zorst will be simple. I have a drive shaft yoke now so might get out there tonight and make a start on it.
The reason for removal is the clutch pivot spacer. I suspect I have a roll top clutch and it didn't need the spacer! Needs a different throwout bearing too so I've been told.