I'd source all the parts separately, theres some amazing deals to be had, then maybe if you then take all the bits to BLB and ask them to build it, or any local bike shop really. My local bike shop would build a bike from just a frame for £25, but it's much more fun to get a couple of tools (<£50) and do it yourself, time and time again.
blb = Brick Lane Bikes.
I'd source all the parts separately, theres some amazing deals to be had, then maybe if you then take all the bits to BLB and ask them to build it, or any local bike shop really. My local bike shop would build a bike from just a frame for £25, but it's much more fun to get a couple of tools (<£50) and do it yourself, time and time again.