ideal icos 'lf' fault - tried everything. Help!!!

[PEDANTICVINDICTIVEMAN]

Those who said ignition kit and gas valve appear to have been correct. That's what the engineers eventually fitted and it seems to have sorted the problem out. They fit both on the same day, so can't say if it was one or the other, but regardless it's sorted. I did wave all your suggestions in front of their noses, but i think they needed to go through their own process of elimination. Thanks to all of you.

Just moved house. Thought I'd get away from the problem, but no prizes for guessing what kind of boiler i've got! oh well, at least i'll know what to do when this one goes wrong! lol Thank you all.

errrrr a Ferroli ?, good luck with that then.