Dizzy girl needs advice on water hammer

The 'train' rushing through my house everytime I turn a tap on / off is now causing extreme stress.
Any sudden demand / sudden turning off such as via the washer causes the problem, turning taps on / off very slowly does'nt - but I mean SLOW!!
The plumber said ''loose pipe causing vibration''so I've secured all pipework with clips & lagged with foam tube at the same time to make them rigid where possible & to absorb any vibrations. Checked all the valves appear to be in the open position.
I've had my (Worester Bosch ) boiler checked, Brit Gas said '' no problems with the boiler, your water pressure is too high''
United Utilities say the water pressure is within reasonable levels @ 2.5.
I can reduce the banging slightly by reducing the flow by the stop cock but that makes my boiler bang.
Could an expansion valve sort this? what exactly does that do? I need to understand this problem more so I can find the right person to sort this out for me. Any advice appreciated.

hi dizzy i would tighten the gland nut on the stop cock quite a common problem

andymac147 said:

hi dizzy i would tighten the gland nut on the stop cock quite a common problem

Click to expand...

Eh?

More than likely that a tap washer or a ballvalve washer is the source of your problem.

I had a clunk every time I closed Hot and cold taps (mains fed) which was infuriating. I tried turning down the stoptap which did help but reduced the flow!

The solution............... I changed the whole stop tap and BINGO, no more clunk.

Install one of these and hoepfully you will fine

http://www.toolstation.com/shop/Plu...ater+Shock+Arrestor+12+MBSP/d20/sd2696/p93058

Did Utilities United actually test/ measure the pressure IN your house @ a Tap or did some pen pusher tell you what his computer screen said for your area/street