Fitting smaller diameter ground lights in paving

[chellochi]

I installed some 240v GU10 ground lights in my patio, which have proven to be an unmitigated disaster (filling up with water and generally not working). Being GU10, they are quite large diameter compared to most other products on the market (a 100mm cut out). I'm now trying to figure out how to reduce the diameter of the cut outs eg to 80mm. What I'm thinking is that I use some pvc pipe and fill the gap between that and the existing cut out with concrete. I can put some resin based joint filler on top of it which will make any exposed bits after installing the new lights look similar to the existing joints between the paving slabs. Does this sound sensible? Any better suggestions?

 

[He who knows]

Must be loads of ground lights around which will drop in?