The water upstairs is only just slightly warm in the bath and sink, no matter how long I run the tap for, the water downstairs gets hot but only after being run for a minute or two. The heating appears to work OK although sometimes the pressure does lower over time, but even when at the proper pressure it still does not work upstairs properly, shower upstairs is good but that is electric? Please help! :)

Do you have a tank, or tankless off the boiler, or tankless separate? And how old is it? Is it cold where you are? Are pipes running up an outside wall?

Tankless can get clogged with mineral deposits and not enough water can heat up as it flows by the flame.
That's just one reason.

If you have what is called in the UK, a 'Combi boiler' system, the tap water is taken instantaniously from the boiler and will come out of the tap at a heat relative to the speed of the water. (the combi boiler is also a central heating system as well as giving hot water to your sinks and bath).

In the winter it will take time for the water to get hot at the tap end compaired to the summer, and the further your tap is from the boiler the longer it takes to get hot, and if you are running a bath, you will have to slow the water speed down at the tap to get it heating.

If you have not changed the way you run your taps in summer and winter, then the problem lies with the heat efficiency from the boiler.

The combi boiler has two thermostat settings, one showing a symbol for a radiator (thats the cental heating setting) and one showing a tap (thats the tap water setting), You will have to turn up the thermostat on the tap setting, to get hotter water from the boiler.

Hope that helps.

Cheers ColinD.