My new NC has the original screen on it, and from my experience of trying to get it off at the weekend, I can see why.

The screen bolts have flat heads, don't screw out, and don't push out. I am at a complete loss as of how to get them off!

If they are in fact the original screen bolts, does anyone have any experience of getting the bloody things off?

I think they're single use, I got a pair of side cutters, nipped all of the inside tips off, then squashed them with a pair of normal pliers. Then slid a thin flat bladed screw driver under the washer and popped them off too :)

They're riveted on. I'd suggest drilling them out with a thin drill bit.