Need spherical white rubber/plastic washer/disc

[WaterTight]

Or something similar of a decorative nature...Needs to be slightly larger than the conical covers (maybe 2cm's greater in diametre?) that meet the wall to cover the pipes on a bar mixer shower. Small but visible chip out of tile just peeping out from one of the covers, happened when drilling holes. Plan would be to install it just behind covers so it looks like part of design and covers crack. Thought of silicone but too rough a look, don't want to move shower valve as it's perfectly positioned. Any ideas?

 

[REDSAW]

you mean like one of these but with a bigger hole drilled in it!!!!!!!!

 

[WaterTight]

Hmm. I'm dumb enough to have forgotten to take a measurement of the shower cover's diametres with me from job but when I get them I might just prance around B+Q looking at all things spherical. One of those types of things might be bang on the money.