It never ceases to amaze me that you always get at least 1 obnoxious know all on these sites , Chris R sole.
I have found what I needed thanks to other more helpful people on DIYnot.com and will be fitting it when it arrives. :evil:
Have a biasi combi boiler, having problem with hot water.
Central heating works okay but no hot water unless you run taps really slow. Boiler only 2 years old.