The two symptoms indicate the same problem. The igniton sequence has to prove that the fan is running before it will fire up. The solution may be the a.p.s which is mains voltage (isolate before any testing). Or it may be the sensing tubes which could involve opening the combustion chamber( gas regulations/ corgi registered only). I have to say that the last time i tried to enquire about parts for a netaheat i was told that most parts were obsolete and not available. Try your local corgi reg. engineer's. They may have more luck than i did.
How long have you had this old beastie anyway? Isn't it time for a nice shiney condensor?
T.H.S
May 2007