I can also recommend Aria!
I found a cracked kitchen ceiling with water dripping through it on Christmas morning - great timing.
I turned the water off for two days, and phoned Aria on 27th. He was out of London, but called in to have a look that evening, after a long journey back bogged down in traffic.
He kept me fully informed of the delays.
He must have been really tired after the long drive, but he went to great lengths to find the source of the leak and make sure there weren't any others.
It was a slow leak from a crack in a connection to/part of my concealed toilet cistern, and must have been going on for months or longer.
Aria came back the following day and fitted a new part, which was tricky due to very limited space, and he made quite sure that the leak was gone before he left.
He explained everything clearly to me at every stage, and I feel he went above and beyond. He was also reasonably priced.
I will definitely use him next time I need a plumber!