You could consider ripping out the shower base and tiling the existing 830 wide and extend that all the way to the existing bathroom wall at the opposite end of the bathroom wall. It would create one wall at an angle but with a seamless glass shower screen and a new tiled floor and walls it wouldn't look out of place. That would allow far better body manoeuvring in the shower.

We had a similar situation with our feature wall bathroom tiles. We chose 600 tiles for floor/walls and feature tile and wanted the grout lines to all line up around the room. However, the feature tile was measuring at 595 and the grout lines looked wrong. I was told that tiles sizes are ‘nominal’ and variations can exist in styles and even batches. We addressed the problem by off-centering the feature tiles, meaning that the horizontal grout lines on the feature wall tiles met half way through the regular tile so it looked deliberate, rather than a mistake. Does that make sense? Would that be a possibility for you? The problem with the tiles being 2mm out is that with every grout line you add another 2mm out so by the end of the row of tiles the discrepancy can be quite obvious.

The size of floor tile: 300 x 300 mm and the size of wall tile: 300 x 600mm The floor tile and wall tile do not align at all. It looks unprofessional. Should the tiler redo the job? Thanks for your advice.

My friend used Dulux renovation paint and it works beautifully, she renovated her ensuite, follow directions for a complete makeover