Alec wrote:
I'm trying to replace the broken hinges on top-opening uPVC double
glazed unit. But some of the screws attaching them to the frame have
rusted through. I sprayed WD40 but I get no grip at all with my
screwdriver. Is there a way to remove the screws without causing
damage to the frame? TIA.

Assuming they are crosshead, get the apropriate anti cam out rib
screwdriver bit and undo them.

MrCheerful