So house went up for sale this week. First viewings booked for Sunday.
The boiler is old and has been a bit dodgy for a while.
Plumber came round today to try and fix it. He thinks it could be the fan, or possibly the gas valve, but not certain. Fan would cost £300, bit then valves may also need to be replaced.
Alternatively He can replace like with like on Friday and replace whole boiler for £2k.
WWYD? It's a lot of money to shell out that we won't get the benefit of, so I'm loathe to do it, but there's no guarantee the patching up will work in time for first viewings.