Harry Bloomfield wrote in
:

has brought this to us :
I have asked for a plumber to look at it now - I'll let you know
after he has has been. Cheers.

That is not DIY!


Wrong shower head? Is it on a flexible hose - is it kinked or too narrow.
Can you remove it and check flow from valve. (Time it to fill a bucket)
Then repeat with it reinstalled.