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I wouldn't want to be your tiler. It's very difficult to reach the level you're expecting. Tiling in general is one of the areas that cause trades problems. I've done a lot of tiling and most of it meets the householders expectations but it's the one area where you can easily lose a client through disappointment and in most cases with the best will in the world no one is going to meet their expectations. It's also very difficult to alter unlike a lot of work.
In some cases planning makes a difference, i.e. you tell the tiler start at the window, half tiles in the corner if that's what you want. Specify exactly the edging and trim in advance etc. Choosing tile types and sizes that are sympathetic to the building/room size helps too. I've seen a few trends come and go and the metro tile is full swing right now, by the time every tradesman has done a few rooms of it the rest of the population will be giving it a rest and so the cycle starts again.
tldr, he's probably doing his absolute best and sweating bullets. If it's not grouted yet then I'm afraid you'll have to wait to see the end effect as grouting makes a big perceptual difference, especially to gap imperfections.
Part of this is I just don’t know how hard it is to get perfect lines on metro tiles in a Victorian house with less than perfect walls. And I am very detail oriented so these things jump out at me.