Darkbreeze :
Yes, like I said, and USAFRet said as well, contacting them again is very likely to get a different response each time. Asking to speak with a supervisor is also a viable step if you don't get a favorable tech on the line.
Contacted support again. Technician still seemed to be having problems getting it to activate, then he made some changes and restarted the machine. Blank screen, reboot, blank screen. Yup, the support tech had managed to screw up my windows installation and I was left with no option but to format hard drive and reinstall. Thankfully I have a boot drive and all my other data on separate drives. Problem is I'm a) still installing and updating windows, drivers etc., b) have lost all the saved passwords to webpages (iplayer etc. so my mrs isn't too happy with me) and c) windows still won't activate.
But I did find this on the windows support page though;
" If Windows was preinstalled on the PC, then a new license is required if you have made a change such as replacing the motherboard. "
So perhaps they aren't too happy to help with hardware changes. Although I've changed this motherboard before and activated windows 10 so this statement on their support page isn't exactly true either.
Either way I'm gonna talk to a support manager because I'm not happy that they screwed up my machine.