So, had a plumber check and another builder (
i have some other work that needs doing before baby arrives)
@conny - thanks - you've pretty much covered what the plumber said. The builder who was talking about freezing pipes.. sent a quote with T&Cs that fit two A4 pages.. and basically stated he'd be liable for nothing.. think i'll give him a wide birth..
@Hugh Jaleak - thanks, i think after a bit of thought it was very obvious this builder (
and a few others) didn't want to 'fiddle' with what he considered beneath him and wanted the big job only, which they'd charge a hefty amount for....
The plumber advised it was just as easy to fit hot as it would to fit the cold water, so that if i ever wanted hot water, pipe is already there
(all other builders have only mentioned cold, as if hot would be too much effort). He also advised that with a bit of manoevering he could put the waste water back into the area that all the other water is going. It would mean the pipe would be angled in lower than the others so it sloped enough, but to be honest, it seems like the neatest and best possible solution. (
He did mention its legally possible for the waste water to go into the manhole, where all the water is gathering).
I've asked him to quote what he'd charge, as i'm almost tempted to get him to do the plumbing and then get the builder to skim/plaster walls and extend the electrical point, at least this way i'd know that the plumbing is done properly.
The builder - i basically asked him to quote for doing it exactly as the plumber had said and see what comes back, he seemed fine with it and didn't try to discourage with 'other ways' to do it.. let's see..
Thank you all for your help and guidance, has helped me make sure i've asked the right questions and make sure that i involve the right people/tradesman!