I've just moved into a new house where the original owner fitted a lot of different downlights. He was a builder by trade, and he got what I suspect were an assortment of over-orders for industrial/commercial downlights, so not only are they all blaring white (and non-adjustable), but they're also in a variety of different sizes.

I'm going to replace them all with GU10 smart bulbs, of which I have several already and the infrastructure to go with it. This isn't too much of an issue for more than half of them, as the lights & the ceiling holes are a relatively standard size. The problem is that the rest of the lights are pretty big - like, way larger than average.

I ordered a bunch of these standard GU10 downlight fittings: A GU10 light fitting

These have an outer diameter of 90mm, and a hole-cut diameter of 65-70mm. But the troublesome LED downlights I'm trying to replace have an outer diameter of 130mm:

Collingwood Thea LED showing an outer diameter of 130mm

...and the hole cut in the ceiling is 120mm. This means that the spring clips for the standard 90mm GU10 fitting barely touch the sides when they're down, let alone providing any tension:

My paltry 90mm fitting in a 120mm hole in the ceiling

I know that there are large 'cover-up' plates available, but they're literally plastic doughnut holes intended to cover scuff marks and ragged hole cuts, rather than make up for the fact that the fitting won't fit.

So what are my options? Are there any oversized GU10 fittings I should be looking for that I haven't found? I'm in the UK, and I'm faced with replacing around 40(!) of these (there are ~110 in the house total), so really don't want to have to re-plaster several ceilings just for the sake of slightly smaller holes.

4 Answers 4


It turns out that converter/conversion kit was the magic word I was missing. After doing some digging for 'downlight converter 120mm', I found these well-priced converter kits specifically for inserting the standard 90mm GU10 fittings into holes up to 125mm. Here's one fitted in the hole (but with no bulb):

Picture of the Saxby downlight converter fitted into the ceiling

And here's what it looks like out of the box:

The verse of the same Saxby downlight converter

The outer ring and the inner GU10 fitting are actually separate, and the only main difference is that the GU10 fitting has much larger springs than the other 'standard'-sized ones I purchased before:

GU10 fitting separated from the outer ring, showing much larger springs Separate outer ring

bobflux's answer is a great option too, and definitely worth considering.

  • Nice catch! I'm probably going to need some of these too in the future...
    – bobflux
    Commented Oct 16, 2021 at 20:17

From the size of the hole, they look like 120mm downlights.

There are fixtures for GU10 bulbs compatible with 120mm hole. Try searching "120mm GU10" or "GU10 dome". The bulb is recessed, which is easier on the eyes.

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If you get GU10 smart bulbs, most likely the same manufacturer will offer compatible downlights in this size. So you could also use that.

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  • Ah, I'd seen some domed light fixtures, but none of this size. My smart-bulb ecosystem is Philips Hue, and although they do do the flat panel-light style, they're only available in the US, and are perpetually out of stock. This is a great answer, but I found something sort of similar - just about to post an answer myself 👍🏻
    – indextwo
    Commented Oct 16, 2021 at 19:09

I'd say a "goof" ring or "beauty ring" are probably your best option. They go into the existing hole, and much like your replacement bulb, use springs to hold on and cover the edge of the hole.

It looks like these might fit your dimensions: R&M Line Filling ring for recessed spotlights

  • 1
    These are the ones I've seen a lot of, but I've never seen any pictures or details of how they fit in - I can't see anything about them having their own springs. They just appear to be flat discs. I assumed they fit over the existing small GU10 fitting, but as that's too small to fit in place I assumed these wouldn't work.
    – indextwo
    Commented Oct 15, 2021 at 9:18

If you only expect to use LED or low power lightbulbs: One of hacks I've seen is to get a cardboard tube (like the one a carpet comes on, or one for carrying posters), cut a ring from it and glue into the hole. This provides a nice round grip for the lights. It can be also easily trimmed flush and painted to match. Nearby building materials supermarket may have a tubes for sale or even leftovers from their carpets, you only need an inch per light, at most.

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