I think a few people have had issues with horseshoe plates snapping bolts, one of those people will be able to confirm though!
Its a rather large bolt to drill out is that, I would probably try taking the hub off and cutting a slot in the centre with a small disc on a dremel. It should turn out without much force, there's no tension on it so worth a try.. Or try tap it round with a centre pop and a hammer
Yeah it did occurr to me that I have been very lucky to spot it. That soon wore off though after a few hours of drilling. Managed to get a large stud remover in but just wouldn't budge. Might need to try a tap.
Anyone selling a rear nearside hub just in case?