Closing down a house for a few months

If you will be away over the winter have you considered the effects of cold and damp, even freezing pipes?
If you do not want to keep some level of heating on then I think you would need to drain your tanks and heating system ( if you are using rads). That's just my opinion.
Let your insurance know , house will be unoccupied. I think this is necessary if more than 30 consecutive days. Check your policy.
Have your post rerouted or collected regularly.
Opt for electronic billing on utilities and bank statements to reduce post and keep up to date.
If you have someone to check periodically that would be a big advantage.

I would not turn off power. I would use timers on some lights to deter would be intruders. You could also fit ultrasonic devices to deter vermin.