Dry, itchy patches of skin... but only after moving to London from the country?

It could either be the water or the atmospheric air in London. My recommendations would be to try using a water filter, then if that makes a difference you know it's the water. Also try a much richer moisturiser, which should help if it's the atmosphere. Mostly I think it's probably just getting used to the new atmosphere, the air in the country is much for fresh and clean.