Hoping you might see this @PigletJohn 
I've just had a new exposed shower valve fitted which has hot & cold inlets horizontally. The first thing I noticed on seeing the competed work was that the fitting is 5mm off horizontal, so it looks wonky. For the money I'm paying I would expect it to be perfectly level but am I being unreasonable? I can see that rectifying this will mean cutting new tiles behind as screw holes will have to be changed. But surely getting your fittings straight should be a basic plumbing requirement. All pipework was made new so it's not an issue of existing supply pipes being unlevel.