: In that case it's an 85° angle and you need to cut the skirting 42.5° : which is hard to do
Not if you use a Skilsaw set at 47½° and turn the work over, like I said in the first place.
: If the skirting is too high and you have to cut it with a Skilsaw : (which I think would be horribly inaccurate)
Not if you run the saw along a clamped fence.
Anyway, this is not precision engineering. Graham, assuming you are fixing moulded softwood or MDF to be painted, I would suggest you cut the mitre at
45° any way you can and if this leaves any gaps in the joint that you're not happy with, all you have to do is *very* lightly plane or sand off the cut faces towards the rear edge to tighten the angle (it's called "easing"), until you're happy with it. Maybe you could try it with a couple of scrap ends first.Peter