I've got one, it was the only way to get a bath in as well in what was previously a shower room. I got the one from Victoria Plumbing. The tails on the taps were too short and the plumber had to improvise. he tried to sort getting replacements from VP but the people on the phone there just didn't understand what he was talking about.
Another plumber saw it later and was very dubious. He said water from the sink, teeth brushing and hand washing etc, could get mixed up with the drinking water supply due to the way it was designed. He was so shocked I didn't tell him I save on water by filling the cistern with old bath water. The sink bit does lift off for washing. Once I saw how much hair had got trapped inside I no longer use bath water very often
As it's made it possible for me to have a bath I love it, but don't really know about this feeding back of grey water into the drinking water. My first plumber who installed it didn't mention this.