It sounds high to me, although I paid around £500 combined Elec/Gas last quarter. I have a larger place.
Follow cassa's advice, and be concerned if it is still spinning when all is off.
Then insist on a meter check, although this doesn't always work. In my old place which was empty for a while, I was being changed a large amount when I knew the only use was a few electrical DIY tools on the weekend and a few hours of lighting. Took ages and involved the ombudsman before they decided to drop their claim.
Best of luck, Hope you find something to account for it.