That is a thermostatic setup and is the best type...as it means that you never get a variation in water temperature regardless of flow or other conditions in the house.
This is fine in a bath I suppose but having this setup in washbasin/sink is a killer. I have lived in many houses in London and most of them had 2 taps. Even now in my own house which was build in the 60s I have 2 taps in every possible location. When I do some washing up I have to constantly swap between hot to cold water, its the same when using washbasin in the bathroom. But this will be gone once I have my kitchen/bathroom replaced.
