R
rocker
Why not just cut a bit of plasterboard in a 95mm circle, pop two bits of batten in the existing hole so they are just visible on two sides of it and secure them with a few drywall screws, then put your new circle into the hole and screw through it into the battens. Voila, now just skim a tiny bit of plaster or even polyfilla over it and when dry, re-drill your holes. OK they'll have to paint it again but it's better than having a whole new ceiling, surely?