Almost every no-heating call we take in January could have been caught in October. These are the checks worth doing before the first hard frost.
Run the heating before you need it
Fire the system up for an hour in early autumn and walk round every radiator. Faults found in September are an appointment; the same fault in January is an emergency, usually during a cold snap when everyone else is calling too.
Bleed radiators and check the pressure
Bleed any radiator that is cool at the top, then top the system pressure back to roughly 1 to 1.5 bar when cold. If pressure keeps dropping week after week, there is a leak or a failed expansion vessel that needs investigating.
Protect the condensate pipe
If your boiler's condensate pipe runs outside, insulate it properly or have it re-routed. A frozen condensate is the single most common reason a modern boiler locks out on a freezing morning in Forth, Shotts or Lanark.
Book the service now, not in December
Annual servicing keeps warranties valid and catches wear before it becomes failure. Autumn diaries fill quickly, so booking early gets you a slot that suits you rather than the first gap available.