DJC:
Did you get it fixed? Mine started throwing exactly the same issue right after I first read this thread (you jinxed it, thanks for that).Just had mine sorted and the gasket had gone allowing too much air in to the combustion chamber to actually light. Since I’ve had it (about a year) it’s always had a lot of smoke starting up, that was because of the excess air coming in but apparently wasn’t bad enough to stop it lighting until now.
It is fixed but I couldn’t tell you what was done. Bunk was lifted and and a couple of new parts fitted because I saw the empty boxes, but can’t elaborate any more. Took the fitter about 30 mins.