More reasonable than the £1000 British Gas wanted.
But if as both respondents say the knocking won't necessarily go away it looks like I may as well save my money and live with it.
Thanks anyway for the replies.
British Gas installed a new Worcester Junior 28i combi boiler last year and I have been told this is 'top of the range'. I was hoping and expecting that this would cure the almost constant knocking coming from I don't know where in the system whenever the boiler is on, but this has not been the case...
