Joy plumbing have always done the job well for me, and can normally come within a couple of days, its just that they are an expensive way of getting the job done. Someone once said that they offer 3 kinds of service, cheap, good and fast, but you can only choose 2 - joy plumbing are good and sort of fast, definitely not cheap! I would recommend them, as long as cost isn't your main priority. Be aware that all prices are before VAT, so another 20% has to be added, unless you're a VAT registered company this is very relevant