
Any photos of the mashup in question? To see what we have to work with?
We cut new grooves in to the screw when this happens with an elec saw and then use a flat screwdriven or an elec drill with a flat screwdriver on it (after a lot of wd40 and some banging between the screw head and the hol)e. But i guess since you can't get a drill in there there is too little space to do that?
Sadly that wont work as there is no room to get in there.
Maybe try a RIBE or polydrive bit of the same size and see if it gets better purchase.

Cheers for all the advice chaps.
Im thinking about admitting defeat now though, i really am useless at this sort of thing![]()
worst case just drill it out and re-tap with a slightly larger bore
direct and forceful, or manly, ggggrrrrr
do it with your chest hair out and a utility belt for maximum effect
Oh yes i strode out to the barn this morning tools in hand,in a manly fashion, ready for another fantastic bit of Marks famous motoring DIY, i saw the wife and her 2 mates sniggering, but i wasnt deterred!
After 20 minutes of cursing i strode back indoors and slammed into me office, to ask on here.
Another fine days work, looking good!

as long as they don't know of your defeat you still hold the upper hand, just go outside and saw through some wood, then nail said wood onto something, then drill a screw into it and hang your utility belt on it.
trust me their pants will dampen![]()