I agree with mfwolfe it is a definite slip hazzard ( if it must be concrete have the installer add silca to the final coat of sealer) to add slip resistance but you should consider cork tile as a alternative lots of colors, naturally warm underfoot, good in wet spaces ( not in shower of course) check out sites like ( Expanko) cork floors, some neat stuff available - shower floor done in small mosaic tile will minimize slipping and take any settling in slab in stride

Difficult- the tiles and floor match beautifully it's just the laminate. Don't think brown works as grey tile has blue undertone Have you tried a navy against the tiles? I have navy laminate in one bathroom with osprey ceasarstone benchtop and warm grey tiles and looks great Thing is though laminate mist has to go with vanity top and splashback so if marble feature only above bath then could use White as clashes with marble but nice with grey tile and floor So hard nearly there

Hi, where is the 'dirty' part of the tiles? My suggestion is that the tiles were not actually dirty, but had a variation in the finish across the board that was only noticeable when they were laid. This is a good sign as it means that the tiles have been hand made or at least hand finished. Putting the acid on them will have damaged the surface. I do not recommend sanding as you risk losing the pattern and damaging further.

The cracks are in our walls though I note our old tiles in our bathroom floor have lifted slightly so I suspect cracking may be an issue for us?? But I will explore the polished concrete/terrazzo option if you think it can be overcome as this is certainly our preference. We moved into our home recently and have basically lived downstairs so have not used the bathroom upstairs at all. A guest showered in it one time and it leaked through to our bedroom ceiling!! So we suspect there is an issue with the waterproofing and there are cracked tiles however we won't really know what the issue is until we pull it all out to see what is happening under the tiles. Thanks for your comments Ann I've appreciated your insights - good to talk with someone who has actually lived with these floorings rather than just going on what you read or are told by a salesperson.