If anyone is interested I have sorted the problem - cost me 80 dollars but worth it for the lack of aggrivation!Bought a recovery tool called R-Studio which re-built the data with no hassle at all - all is well with the world.
Until the next Micros&*t hiccup....
Cheers
DtG
BTW - I have tried the same procedure for upgrading to dynamic disk subsequently to see if I could re-create the problem and I couldn't - all the rest went well. I can only assume some sort of incompatibility between Linix and W2K caused it.