Bugger.
boiler seems to have finally expired overnight. Arse Arse Arse.
Symptoms do seem to suggest thermocouple (or gas value – *gulp*) but looking at it it appears that I need to remove the entire gas front (that we never use and hate the look of!) to get at the workings of the back boiler. I’m not too keen to do this but if needs must maybe I’ll have a go….hmmmm
Waiting for father-in-laws plumber mate to ring us – hopefully he will feel sorry for us 
Of course, sods law is that Beccas cough turned worse yesterday and she is now on antibiotics for a chest infection – great timing!
ARRRRRGGGGGHHHHHH.
I hope it gets sorted quickly!