If you lost all the electricity in the whole cottage, then probably you have an RCD near the fusebox which had tripped. Older houses in rural areas, especially with overhead power lines, are often wired that way, though it does not meet modern standards.
Sadly you could probably have switched it back on again, you might have had to turn off the box for the storage heaters as maybe one of them is damp or faulty and caused the trip.
Each heater would normally take 15Amps or less so unlikely to trip the company fuse (main fuse) in your cottage as it is likely to be at least 60 amps, and company fuses are very tolerant of overloads.
If you were charging all the storage heaters, and several convector heaters, and the immersion heater, and cooking a big christmas dinner on an electric cooker, or using an electric shower at the same time, then the company fuse might blow, but it takes a lot. No other fuse or breaker should cut power to the whole dwelling, except an RCD on the incomer.
If you take some photos of the meters, fuseboxes and timers, and the various cables around and between them, and upload the pics to your profile, I could make a better guess.