Soooo...I checked the ocharts 'scope' for S63 and there it was - "Install permits will only be valid for the
hardware and operating system combination in place in the moment when the Fingerprint was generated to create the install permit"
I had upgraded to the latest operating system on my Mac since
buying my original
permit, so guessed that might be the problem.
I bought a new Userpermit and then it all fell into place after that. Lots of wasted hours but happy to finally be up and running.
Best regards all..