But it's a rabbit hole to go down, we have 12 in our kitchen/dining area 2 banks of 6. but as 6 of them are in the kitchen they have (or should) be at least IP44 (I think) or better still IP65 so the cheap ones are £7.48 from Screwfix, £90 in total, these are also round our existing ones are square, ceiling will then need decorating, that is assuming that the holes of the existing ones are 72mm like these. Then there's the hassle of fitting them & then the big one, how long is the ROI & is it worth it.