From westcroft. It looks like the shower valve - when runnning hot tap luke warm I can actually hear the water running through the shower unit if I press my ear to the shower. Noise stops when tap water is running hot.
Shower company very good - sending two new elbows f.o.c. with non return...
Had Vaillant installed in June 2007 - full system flush on rads etc. Had new bathroom fitted month later with mixer shower & mixer sink tap. All worked perfectly for three months.
In September 2007 the inline cold water feed to the boiler was turned off at mains to refit an in line filter...