Okay disk is off...finaly. Got the wd40, juiced it up, left it for a while. I then tried whacking in a crosshead, which snapped when trying to undo the nut, i dont have any torx parts

, i dident bother with the screwdriver and dremel method as i'd end up snapping those aswell, the bastad was pretty damn tight in there! I ended up drilling into it to get it off.
Anyway i've learnt my lesson not to do those allen nuts so damn tight! Thanks alot for the help everyone much apreciated!