Rear bumper removal

[geraintthomas]

So I went ahead and tried to remove the rear bumper. Almost there, except one of the cross-point screws on the underside has completely rounded off.

My question is this - on the under side of the rear bumper there are 4 torx screws, and 2 cross point screws. Do the cross point screws need to be removed? If not I can ignore the rounded cross point and remove the rest, but if they do I've got no chance until someone can drill it out.

Thanks