Potterton back boiler not firing

[cold]

I have got a Potterton Housewarmer 45 or 55 (not sure which) boiler, which is situated behind the gas fire. The ignition (located on the right hand side of the fire) has suddenly stopped working and so the boiler is not firing up. Occassionally it will click and work, but is a very erratic. Any ideas what the problem would be, I've tried calling some CORGI registered plumbers, but they've been slow to respond because it's apparently an old boiler and they are not sure whether the parts are still available.

Is this likely to be a situation where I need to get a brand new boiler.

 

[ChrisR]

YOu can still get the bits I believe. If it was working OK, why replace it if you can mend it for say £200? It won't last forever but if you're stuck with a back boiler they aren't much different now.