Further to Blueskiers idea, you could screw batons to the wall and fit plasterboard to that yourself meaning you would only need to pay out to skim the wall if you wanted such a finish. Or even fit upvc cladding a piece at a time which is relatively easy.
I never thought of that, good idea, pvc cladding I don't like, but screwing battens to the wall, and then boarding, with a new piece of skirting board is a brilliant idea, that would solve problem of
trying to find way to fill in big hole (see pic).
The only issue I could see is getting the door back on to cover fuse board as brackets just about fit, so would stick out more with plaster board and battens.
I will cross that bridge when I get to it.
Thank you for that idea, that's the one I am going for.
Just need to find plasterer afetrwards.