And Finally,

After much head scratching and swapping of parts I have eventually sourced the problem ... Engine Loom.

I completely removed the loom from the engine stripped back some of the protective covering, mainly around the ends of the plenum, and found a couple of suspect wires. Later found that these feed both the phase sensor and the TDC sensor!!! Also on reconnecting the loom found that the centre of the 3 connectors on the bulk-head and a broken tab, hence the connector did not have a 100% true connection.

Well guys many thnaks for all your suggestion and input, lets hope it is'nt needed again for sometime.

Cheers
G