Sudden low hot water pressure upstairs bathroom

Ada2020

Hello,
We have low hot water pressure in the upstairs bathroom - bath/shower only. Sink tap seems fine.
The pressure was fine until few weeks ago when is suddenly dropped and now the hot water only treakles out of the bath tap or shower.... we have reasonably new combi boiler in the garage, maybe around five years old.

Any ideas what's gone wrong?
Thank you for your help!

neilmcl

Is the shower separate to the bath tap or is it a combined bath/shower mixer?

Dottydolittle

I had a new bathroom just before lockdown. I find that the water pressure is low upstairs compared to the taps downstairs, in fact if I am filling the bath I cannot simultaneously use the sink tap. The builders finally came back yesterday and said there was nothing they can do as they think there is a leak somewhere in my plumbing. What can I do?