Thanks for the many replies guys, very informative. The manifold reading is the same with the KTS, solus pro and S.M Vacumm gauge.
The rough starting after left for a while was apparent before the belt went, obviously i dont know what the manifold pressure was then? It seems to fit an earlier description of a problem with the valve lifters as it misfires from cold and an apparent tapping noise can be heard once run at 2000rpm and warmed it settles and vacumm goes down to 600 hpa (from 800 when missing).
Coil changed made no difference so old one put back?