Fault L2

This is all extremely bad news. although I do accept a 1st world problem. Got back yesterday early evening and house v cold. In fact colder inside than out. Googled this fault code (on my combi boiler) but discounted all the easily correctable issues with no luck. Called (website down) British Gas Homecare to whom i pay a monthly fee. They are sending an engineer - Wednesday afternoon. I said that i was cold and miserable. They suggested an extra T shirt and a hat. I confess that I am not impressed with BG Homecare. Hopefully they will turn up on Wednesday. As I have no heating or hot water until they sort it.