I want to fit one of these Please login (registration is free!) to view this link. http://www.plumbworld.co.uk/pressure-equalising-valve-344-230 due to having mains cold and gravity fed hot water with a mixer tap. Is it ok to just saw the copper pipes a few inches below the taps and fit it right there underneath the bath? If so what is the easiest way to make the connections for someone who's not very up-to-speed with plumbing?