Wetwall is actually a brand name of a waterproof paneling system by Shore that's designed to be an alternative to tiles.
I don't believe they can actually get you a true recessed soap dish for Wetwall because making a cutout for it would compromise the panel. If they make such accessories, I haven't seen them. I think it is likely the type that has a "feel" of a recessed accessory but actually sticks out from the wall.
Anyhow, yours is a standard tiled wall.