A few tips from the forum.
"I have used the 45mm Rubi hole cutter in 9mm ceramic wall tiles successfully. Cost just a few quid for the cutter."
"Loch boy, rubbi hole cutters and a grinder. All depends on the tile and the desired finish"
"I use my makita, I mark the tiles and transfer the mark to the back of the tile. You can get off alittle because the pipe flanges cover and over scoring etc. I also use my diamond hole cutter "
"Transfer the marks onto your tile, grind out the biggest square you can, then nip out the remainder of the hole"