Hi Sofia I definitely think brick lay would work better on the walls in the bathroom purely because you have a 30x30 on the floor and a 30x60 on the wall. You will find the tiles could look out of place trying to stack them. It would be a different matter if they did not share 1 or more dimension. Perhaps in the ensuite, consider doing something like this: [https://www.houzz.com.au/photos/what-architecture-beirutful-house-eclectic-patio-london-phvw-vp~14310278[(https://www.houzz.com.au/photos/what-architecture-beirutful-house-eclectic-patio-london-phvw-vp~14310278) Tile the floor and half way up the back wall with the "floor tiles", perhaps a tile or 2 above the vanity unit and then continue with the white tiles to the ceiling. You could hang your mirror so it covered about 1/4 of the "floor tile" and 3/4 of the white above the centre of the sink. In the main bathroom consider something like this: [https://www.houzz.com.au/photos/victorian-dream-bathroom-victorian-bathroom-london-phvw-vp~39122647[(https://www.houzz.com.au/photos/victorian-dream-bathroom-victorian-bathroom-london-phvw-vp~39122647) Tiling the back wall to the shower in the "floor tile" to the ceiling with the white tiles behind the loo to the ceiling. Alternatively, tiling the entire back wall with the "floor tiles". The first option may make the bathroom feel smaller if the shower takes up more than 1/3 of the back wall. Doing the two different options would give the bathrooms continuity, but also some individuality. I hope this helps. Look forward to perhaps seeing the outcome. James

because the water could seep through the joints between the new tiles and sit between the two layers and affect the seal and also raise the height of the floor and affect the slope to the waste outlets..but, why do you want to retile if you're not using the bathroom??...for immediate resale consider bathroom wall to wall bathroom carpet, new wall paint, new vanity, taps and light fittings which should also be cheaper than tiling over the top and, if it's not allowed by the body corporate, it will be a risk to future sales as it should not satisfy a proper building inspection

Have you priced having the whole lot re waterproofed and tiled? You are already doing the hardest section, it may not be that much more to do the lot. Otherwise agree with above match to the white tiles in the rest of the bathroom. But it will always look like a repair.

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.