Boiler insurance. £100 a year, includes a service, if the boiler breaks down it will be repaired or replaced. Similar thing is available for things like dishwashers and washing machines, but I have never seen the need.

Not op but our mortgage lender offers a “total home warranty” for like $8/month which covers appliances and systems (hvac, boiler, etc). It’s basically appliance insurance. And at that price it’s a pretty good deal when buying a used house.