I've used Mark Eade of M&E Heating a year ago myself and he also did something for my work place a few months later, and was very happy. He did some plumbing and gas works but didn't fix a boiler for me. no connections etc.
020 7231 0209 [email protected]
Glad it worked for you too as it's always a bit scary to recommend someone.
I think he is based near the big Tesco on Old Kent Road, so local too. Fingers crossed he continues like this and keeps customers happy as from my experience tradesmen like him are very rare these days to find I think.