Hi, I think I used another licence after I updated to Window 10 Creator Update. After the update, when I next used Permut8 It complained it was not licenced and went through the licence procedure, During which it said I had used 2 licences, yet I have only ever installed one PC.
Is this a problem?

No, its no problem at all. This is perfectly normal, the counter never resets and there is no fixed limit. We use this counter to recognize shared or spread licenses. It is shown to you so that you can make sure that no one has gotten access to your account / license.

OK thanks..