Pressure dropping

[themill2003]

The pressure is continually dropping on my boiler, even when the heating is not on. This is quite significant - it drops at least 1 whole bar per day and I have to keep topping it up. The boiler has just been serviced and he thought it would now be all right, but it isn't. I can't find any leaks anywhere and I would have thought I might do so with this amount of drop in pressure.
Is there anything else that could be causing this problem, and / or is there any other way of finding any leaks as a lot of the pipework is hidden behind fittings etc?
Am I better to get a plumber in or a boiler specialist. I have boiler insurance with the gas Board.
ANy ideas will be greatly appreciated!

 

[twgas]

check the discharge pipe outside, if its dripping new prv reqd. BG should do this under contract unless you only have apliance cover (1star)

 

[themill2003]

They did check the discharge pipe and said that was Ok.
I live in a flat and if there was some water leaking wouldn't my neighbours below know about it?

 

[twgas]

would expect neighbours below to notice a water leak,
what boiler/system do you have.
you ought to get BG back as they should cover this sort of problem, if you have a 3star contract

 

[themill2003]

perhaps I should ring BG again. Not sure what star service I have.
Could it be that the dial itself is faulty or is this very rare ?
I have an Ideal Response 120