Zero!

Temperature: ZERO
Boiler pressure: ZERO
Oil tank gauge: ZERO

Diagnosis - there was a power-cut while we were away which tripped the fuel-line to the boiler. We'd carefully left the heat on a reduced temperature to fend off the freezing weather, but our best laid plans were foiled, as the temperature both inside and out continued to plummet.

Solution - reset the timer, reset the fuel-line, restart the boiler, wait 48 hours for the house to come up to a reasonable temperature (they never tell you THAT particular down-side of under-floor heating!). The only good thing is that now the oil-tank gauge is back on, it shows that we actually have plenty of oil - phew!

So after a week at 23C+, we're now shivering indoors at 5C. P is wearing all his available clothes all at the same time which is quite amusing. But I don't think I want to live with the Michelin Man for too long.