really bad pressure out of taps

[young plum]

I have recently been asked to fit a shower for a friend when i went to have a look the pressure on hot taps was really bad it had no power.
He said he had 3 diff plumbers out and was charged 3 times and it has not been fixed still bad pressure?
my ques is can i fit a thermostatic mixer valve it is a gravity fed system or will it be no good with bad pressure and has any one got any ideas why pressure is bad both sink and bath

 

[jobloggs]

Where is cold water storage tank? Assuming that system is not pressurised.

 

[JPC]

not enough head ?

blocked pipework

 

[Nige F]

FFS 3 "plumbers" My psychic eye says look for small bore braided tap connectors and cheapo chinese taps

 

[young plum]

The cold water cistern is in the attic above bathroom i will check the taps etc
cheers for the advice

 

[corgiman]

not enough head ?

dont get me started, been married ten years mate

 

[Nige F]

HOW much did he pay the "3 Wise Men"

 

[loafer]

could sum1 plz tell me what head is????? not in the plumbin' sense that is cos i fink dat corgi is alludin to summat entirely different????