Right, odd one this!

Its a worcester combi-boiler.

The little gauge that tells you the pressure of the rads keeps going up past 4bar (should normally be 1-2bar) so you have to drain about a litre out the rads. This happens over about 3-4 days. Its only been doing it the past week or 2.

The pipe to connect the boiler to the water supply is disconnected all the time so cant be going in there!

Any plumbers on here!!??