Hello
We've just had a new bathroom installed and the hot water pressure has decreased so we cannot use the hand held shower. We have checked stop cocks, etc. but no change. Can we install ( or have installed) some sort of pump system which attaches to the hot water tank which is situated in an adjoining bedroom?

More that likely you knocked loose some lime or other contaminent. Check the hand held for pluging and a pump is not what you want. Find the real problem.

Hvac was bang on when he mentioned crud blocking the new installation. Do you flush your water heater on a regular maintenance schedule? Now you're going to hafta open up the shower valve and flush out the valve body, the hand held shower and supplies. Good luck, Tom