Nah. Coving is white, like the ceiling. You still need to cut into the
wall, but at least it is 10cm lower with gravity on your side wrt runs
(and often on a smoother surface).

Ornamental stuff may be white (casting plaster) but the normal 'half
round' is covered in off white cardboard, like plasterboard.

I meant it is white after I've painted it!

Christian.