Good news, I've fixed it ! Car starts OK. Whilst twiddling my thumbs waiting for the Pulse Module to be delivered via eBay, I thought I'd take another look at the RCM.
As I said before, the RCM looked perfect, all solder joints were clean and no sign of burning etc. I had already re-soldered the 3 points indicated in other posts and continuity tested all tracks, coils and contacts OK, so I decided to carefully re-solder every joint, plugged it and hey presto !
Thanks for your advice along the way.
Mick