Intermittent hot water pressure

[Jdubs]

I have an issue with my hot water tap pressure, in the kitchen it occasionally slows to a trickle but I have a mixer tap so I can put my hand over it, turn both hot and cold on and it clears the blockage but its only a temp fix, I also have low pressure in the bathroom taps. Is there a chemical or cleaning method to perminantly fix the block?

J

 

[seco services]

Could be something floating around in the loft cws being drawn to the cylinder supply pipe restricting it.
Could be lump of foam insulation off the cylinder now inside cylinder restricting the draw off pipe at the top of cylinder.

 

[Jdubs]

Makes sense, do you know how I fix it?