Re: Don't want 10
>I have resurrected a Win 8.1 install
Remember if that was originally a Win8 install, you will need to keep you Win8 install media. Because the Win8 key won't work with a Win8.1 install disk, only with Win8 and upgrade via WuP to 8.1.
Hence I expect that the 'Free' Win10 update will be similar, it will only install over a previously activated OS and won't accept a licence key for 7/8/8.1. Hence if you every need to reinstall... it may be simpler to buy a retail copy when MS discount it to a few pounds just as they did with Win8, which could be had for £14.99...