From memory, its just held there by art, or nothing specific! In fact, between the windscreen, the plastic demister vents which protrude through it, the instrument housing cover, and the two aluminium linings which run around the inside of the doors and meet near both ends of the panel, that's pretty much enough to keep it tight. It's getting the panel out from behind those silver frames that's the tricky bit (assuming you want to keep the windscreen IN). That's after you've removed the instrument housing cover, of course.