Soldato
Cheers for the info.
I've ordered a cheapo aquarium heater with thermostat control for next time at least. The office is witout doubt the warmest/best part of the house to ferment in, but it's getting a bit cramped with a brewing bin in here!
I'll leave it longer as you say. If temps do fall too much, I can stick it in a warm tub of water with this heater in (if it arrives in time). I think the main trouble I'll have is with maintaining warmth, as even though the office is usually warm, temps will drop at night by quite a lot. I'll wrap it with the sleeping bag to give it every chance and keep an eye on it.
Same here. I just sterilised the heater and dropped it in the beer/wine