NIce bath. I had a tiler in recently and the tiles ran off on both sides. He said the room was off square which it likely was but he squared off the short wall instead off the long wall. Short wall wouldn't really have been noticeable. Other than that he did a good job.
Looking at the variations and highlights in the glaze these look suspiciously like "moustier" (from fired earth) hand-made tiles from France. I've used them a couple of times - most recently in our kitchen which I re-did last year, as here. (At a huge discount as they were end-of-line - wouldn't normally pay fired earth prices!!) They are a bit of a PITA as they are not particularly flat, vary in size about +/- 1mm and chip like hell when cut. The glaze variations do look nice though when put up with care. (we like them anyway)