Thankls for quick reply. Should have also mentioned, the electrode lead for the piezo igniter has come adrift, I light it manually. Would this have any impact.
Just found this font of knowledge. :)
I have a Potterton Tattler RS46 gas boliler which is over 25 years old.
Last week the pilot light went out, [1st time in 5 years]. It relit straight away. In the meantime I bought a new thermo-couple; today pilot goes out and wont stay on with old or...