Hi, Hope everyone is well. I'm after some advice please. I'm currently having my bathroom tiled floor to ceiling. Tiler started yesterday and has completed 3 walls. Before he left he mentioned that in the top corner near the ceiling there is only a small tile due to uneven walls. Not really able to have a good look due to him working I assumed he meant he had to cut one down to fit where it was uneven. When he left, I had a proper look. In that corner the grout lines don't meet up level. There is about 10-15mm hight difference. I put a laser level around the room lining it up with a grout line on the wall he started on. By the time it hits back where the unntiled wall meets the tiled one it looks like there will be nearly 25mm height difference. My bathroom floor does have a slight slope from one end to the other. It looks like he's started tiling from the floor up. In my brain it says, if he follows the floor level the grout lines will be slightly lower on one end. Am I assuming wrong or will this be corrected as he goes along? I've added some pictures. 1 is where the corner meets and the others shows a laser level around the room that doesn't match up (may have to zoom in). Any advice would be appreciated thanks