Yes, I tried ringing MS and they did not recognise the key so that was a non starter.
I then downloaded an app last night which extracts the key from your software. I did that on the old Lappy and found the correct key, I had 1 letter wrong :

. Went to the download site with new lappy and put key in. Jobs a good un.
So I now have it on both old and new?
Thanks for your suggestions.