That is the plan, I'm back at work all week and the bike is at my dads so won't be able to do anything to it until the weekend

Foamy. Would it be possible to drill n tap a left handed smaller bolt into the head bolt then once fully tightned the old bolt should rise. Or am i being mad.

Left handed taps arent always easy to get hold off and costly. Using an easi out is the same thing but cheaper and easier

I agree but its fun to think out of the box.

a shallow hollow bolt and weld inside, then weld on a head

Well worst case scenario is to take the head off altogether and give it to our guy in station workshops and let him repair it. (he's CNC'ing a new top yoke for project FUCR aswell)