Is the Hot water cylinder located above the first floor (above the kitchen sink) ? If yes that would explain the good pressure on the hot, the cold might simply not have enough head.. More info on layout would be helpful.

The Hot water cylinder is on the same floor as the kitchen sink. The kitchen sink is therefore on the same level as about half way up the hot water cylinder.
I have recently purchased the property so I can only assume that the problem has been evident for some time. I know that the problem was there when I purchased the property
I recently replaced the kitchen sink mixer but the problem was there before I replaced the mixer and the new mixer made absolutely no difference to the problem.

You say kitchen mixer? Single lever? Flexi hoses underneath it?
Most are designed for unequal pressure, low hot, high cold.
Generally performance on equal low pressure water will be poorer on the cold side of things

Hi Guys,

I appreciate your advice very much.
I had a funny feeling that my problem was a bit unusual

Unfortunately I can only get at the pipe work for part of the way to the sink. The rest is in the walls - bugger.

I do have a single lever Sink Mixer with flexible hoses. I was very careful to ask if the mixer was suitable for all pressures. It is a Foreno LT140 Sink Mixer for Unequal/Mains pressure with a min pressure of 25kpa. The sink is more that 2.5m below the level of the water in the roof tank so I think I should have at least 25Kpa.
Could this mixer be the problem and is there any smart way to check it?
I think that the problem pre-dated this Mixer but I could be wrong.

Upgrading the water system would be nice if I had enough money to do it. I think I would need to replace the Cylinder and instal a Pump. What scares me is where to locate the Pump and what the likely costs would be getting power and water pipes to it. Have you any ideas about what this might cost. Even a ballpark estimate of the cost of a Cylinder and Pump would be helpful.

I guess that I should take your good advice and get a plumber to check out system.

Many thanks for you help
Phil

Thanks Bowtieboy

I will take your advice and get a plumber. I do not have a perlator on the faucet.

Just for interests sake I will let you know what we find out.

Phil