Ceiling - take down or board

Plasterboard ceiling that has water damage in one place.
Better to board over or replace with new board. One section has crumbled away.
Attic has the usual fibreglass insulation and this strange stuff between the joists that's like a cross between wool and ground up cardboard.
I've had the artex tested and it's clear of asbestos.

 

looks like an old place. if it’s flat enough board over.

 

Yes it's flat enough, I'll have to do lots of cuts along the back for the curve down to the wall.
Built in 1854, so yes fairly old.

 

if the artex is sound you could build the curve out with bonding coat.

 

Artex is about the only solid thing in the whole house.