dspaul helped me get my Marin (funnily enough) and my friend's Giant done at Greenspeed and they were cheap and extremely good. Prior to that I used a sandblasters in Levenshulme and SprayQuick in Bredbury, good but pricier overall and not quite as nice as Greenspeed... so much so that Paul & I are off back there this week with our soon-to-be-black bits