UPDATE:
I fully expected a 'hassle' with a reinstall WGA but none arrived
- well now it has! After finally transferring the Win7 to a SATA drive from an old IDE I guess M$ reckons there is skullduggery afoot. Too many hardware changes I guess. The initial 'change product key' via first line telephone support did not work so I have to wait until Monday to speak to the next level for reactivation.
I know why they do it, but it is a pain when you ain't 'cheating'.......................