I’ve just purchased a house and have stripped the wallpaper to find this grainy material. From a quick google search it seems to be lime plaster??
Do you agree?
If so how easy is it to remove so I can re-plaster?
Presuming an inside wall, then does it really need to come off? It looks as though it could be dubbed out here & there - cleaned up by scraping over - suction taken up (50:50 Pva and water) - and skimmed over?
Otherwise, it will come off the masonry background easy enough using a hammer action tool with a chisel.
Remove skirting - and cap the outlet cables.
Fix one piece skirting, and take up masonry suction as above.
Is there a length of wood embedded in the wall near the outlet? If so then remove it & make good.