Thanks for your invaluable help. Given that I’m not a complete imbecile and am struggling financially, I don’t see it entirely unreasonable that I should try to sort the issue myself. I’m clearly not going to start “messing around” with the actual gas side of things.
Bit of a strange one - ran the hot tap this morning, the boiler cut out and displayed L2.
I cleaned and checked the ignitor and the probe for continuity - all seemed fine.
Put everything back together and reset the boiler. Now when I turn on the hot tap half way, it heats the water up and...