Well.... ****!

Decided to go back to Windows 8, figured maybe that would fix the problem.
I used my recovery usb stick like I've done a thousand times before. Following the same instructions I've done a thousand times before...



Solved Surface Pro 1 - Build 10122 - Startup Loop, can't login or recover. - Windows 10 Forums

And of course something goes wrong!

"The drive where windows is located is locked, Unlock and try again"
Rebooted. and SPro will now only go to UEFI screen. Can't get into Advanced StartUp or anything.

No warrantee, didn't buy from Microsoft themselves.

Just purchased a used replacement SPro 1 off of ebay for £230, and I honestly think I'm just going to keep it on windows 8.1 update 1. Windows 10 just has too many errors. Yes I know I did something, but like I say I was following the exact same instructions I've done before, so it should have worked. And if there wasn't a mystery problem with my MS Account not recieving Preview Builds I wouldn't have bricked the damn device in the first place.