Electric bill excessive . where do i go for help

Robin9

The scenario of other buildings being connected is looking quite likely.

Following this with the landlord/agent is going to be difficult for you but why not contact the new tenant with your information ?

dogshome

As the consensus of opinion is that this meter is feeding other premises as well as your son's flat, then the new occupiers have the same noose around their neck as your son, so it's well worth contacting them.

The down side is that a wiring distribution problem is nothing to do with n'power, it's down to the re-developer or landlord who may be one and the same.
If your warning to the new tenants does eventually result in new meters and wiring on the site, recovering your son's overpayments will probably need legal action