I think the easiest route is to take down the light (power off) pull the cable through to give you enough to play with, then clean up any rough surface and use one of the fibrous fillers or polyfilla plaster repair, sand down when dry and paint to match. If you are concerned about not having something to screw to, before you fill the hole you can push a batten up through the hole and glue it down with filler ( apply it to the underside of the batten before inserting then filler side down pull it downward to make the filler adhere to the upper surface of the ceiling, mark where the batten will be to screw to .

As the others have said, laying spotlights all over a ceiling just looks brash. They are best around the edges of the room, where the light bounces off walls and serves to give a nice glow, rather than an industrial glare. And I would absolutely advise keeping the central fitting on a separate circuit for a statement pendant - or at the least advise leaving the wiring for that there and hidden in the ceiling, for the potential for one in the future. Spots are massively overused - I have seen a load of period houses here in London made soulless by removing ceiling fittings and ambient lighting for a carpet of spotlights. spots are one aspect of a good lighting design, but should not light a room on their own - too harsh, too directional. Even in utility spaces like kitchens...

So your suggesting wall lights and lamps only. No recessed spots or led strips along beams? We will be having tv unit in alcove furthest from window and a sofa facing fireplace just placed in front of doors on either side. The other half of the room will be a dining area temporarily. Will wall lights be enough and how many? I prefer symmetry in my rooms also. The ceiling to floor is approx 7ft. I’ve read to make a room look higher than it is uplighters are best is this so? If our plans work out the dining area will eventually turn into a quiet area with comfy chairs bookcase etc. My husband is not a fan of wall lights says it restricts you if u want to change furniture around. I love them but with a low ceiling I am unsure how high up they should be not just for best lighting but for furniture arrangement and if they are on a wall where u walk could be an obstacle? I have also posted about my spiral staircase but I put it in the topic design dilemmas but it is about lighting also.

It’s all a matter of taste and style. Try smaller cornicing with the concealed lighting then your ceiling height or room shape won’t be an issue. Combine with table lamps and you’ll create a lovely ambience. If you fancy it, go for it.