Kitchen Tap Suppliers

I live in west London, my provider is South Thames Water.
One of the bathroom much more difficult too. Is this the same water they offer two types of water in the same household?

It depends on how old your house is. If you live in a very old house (before the normal water supply), it is possible that you have made the water separated. (Very, very unlikely). What is the most probable issue of water with you, is that some of the house can be feathered with copper and the other with another material (such as PVC or iron). This would make the water taste just a little different.
Hope this helps