Stevieo
Royal Spin Doctor
Fair point - when I posted, I had it in mind that maybe the grit product had detached from the artex due to the artex surface unexpectedly not allowing the grit to bond properly, for some reason - i.e. if that happened, it would be out of control of the person doing the plastering (aside from overboarding it). If it was a kitchen rather than a lounge, my first thought would've been possible cooking grease on the ceiling.
But the grit is clearly still bonded to the ceiling? No white patches so it can't be cooking grease.
This has destroyed my faith in grit a bit - I thought the stuff was bullet proof