Found this by accident while following the link to Big Train. To be honest I don't remember much about this sitcom, but Sean Lock's a brilliantly funny guy when he's on form and you can't go wrong for a fiver for two series, can you? Here's what Amazon has to say about it.
"Two very different blokes. One small flat. One huge apartment block. It's bound to go wrong, isn't it? Especially when one is morose, sullen and mean-spirited and the other is a bright-eyed innocent with a lot to learn about life. Far from expressing the depressing and futile existence commonly associated with high-rises, 15 Storeys High reveals the many idiosyncrasies and hilarious antics of the diverse residents. There's the man who uses his pitbull as a dumbell, the table-tennis obsessed brothers, the over-the-hill punks and the country and western poet who also fixes washing machines. And of course there's South London's very own answer to the Odd couple, Vince and Errol: a match truly made in heaven. "