Got an C&M Britony boiler that has been loosing pressure for a while.

It appears that the pressure release valve drips to the overflow releasing
the pressure over time, or suddently gives way (say at 2 bar) and drops the
pressure. So far I have lived with this, and just topped up as required.

However! yesterday a leak started within the boiler, after examination the
leak has been progressive (i.e substantial limescale etc) and therefore been
leaking over time from the "air seperator". The leak is to the extent that
any water in the system is lost.

Obviously the air seperator needs replacing (cost about £25.00), would it it
wise to replace the pressure release valve at the same time?