Is the spot lamp on a plasterboard ceiling, if so, remove the existing spot lamp, buy a small piece of plasterboard from your local diy store, measure diameter of main hole and cut out a new circle of plasterboard to fit in this hole. Get somebody to go in to the roof space above the hole and have a small lath of wood to bridge the hole plus a couple of inches. While they hold the lath against the ceiling screw the new circle of plasterboard to the lath with a chipboard screw. Now mix some hardball and skim over the new piece of plasterboard with a plasterers trowel. Including the damaged area to fill it out, this may need a couple of coats or if difficult buy a couple of handfuls of Bonding and mix like the hardwall and fill the damaged area with bonding, then skim level with hardwall.
Paul, December 2014
