These have the bumpy finish as in your picture and are on offer at the moment: https://www.wallsandfloors.co.uk/catrangetiles/brick-metro-tiles/metro-bumpy-tiles/metro-bumpy-gloss-white-tile/19112/ I've ordered from this site before and very good service.

Jonathandb1972, I was thinking of going with a grout that is the same colour or lighter than the grey tile. The hex will be grouted in a medium grey. This has already been done in the loo (the hex) and looks great. Neither are grouted in the above picture. Do you think there will still be issues with where the grout lines are if they are the same or lighter than the tile? Also, where the hex tile in the shower meets the grey tile will mainly be covered by the shower's profile. However, the shower only goes up to about 2m, so there will still be a visible "meeting" of tiles above that. My builder is a little concerned about how this will look as he will have to cut small pieces of tile to fill up the edge, which may stain once they start grouting. I'm keeping my fingers crossed and hoping for the best...

Like this, you mean? Any unevenness in grout lines will be very visible. But it's a nice look.

B&Q have some nice patterned floor tiles. Here's a couple I think would go well with white wall tiles.