mrstella: Actually,
There is a statute of limitation on energy bills. I know this because I worked in the complaints department for Scottish Power. I can'te remember, i think it's something like 2 years, but best to contact Consumer Focus.
That is under the energy providers code of practice on backdated billing, that applies in cases where someone has never received a bill for the property they reside in. It disallows energy providers from backdating a bill for more than One year in that qualifying case.
It used to be Two years, but has now been changed to One year.