Submeter advice

We have just purchased a new property (January) and we have some uncertainties to how things are setup regards electric billing. The property is on a few acres of land and the previous owner still owns fields adjacent to it.

In his field is a barn which he owns and during the sale we agreed to allow a submeter in his barn from our supply that we would bill him from. Sounded simple enough but we didn't really put much thought into it otherwise might not have agreed but everyone was happy and we were in a rush to move!

Basically before we moved in he had an existing supply up to one of the fields adjacent the barn and again before we moved in he fitted a submeter into the barn and had the wiring/fuse panel done from that. Since moving in we haven't got on as well as during the negotiations . We needed to have our supply tested near the cabinet next to his field and the readings were not good with bad earths on our sockets.

I had an electrician out and with effort managed to get him access to the barn. He only had a brief look but the conclusion was he had the good supply and what was routed to us was a bit rubbish with unmarked fuse box and wrong cable sizes etc.

We haven't had chance to do anything about it so far but have asked for readings which he has given us. I left it six months as the readings were that low it seemed extra hassle to do it every month. We now have readings for 6 months and its £36 which seems really low for a big barn with lot of lighting and we later discover he is virtually living there. We haven't that much trust in him due to other villagers comments!

Firstly is there anything I need to do formally to bill him, do we just write a simple letter saying this many units used at this cost and ask a way to pay?

We are not happy with this arrangement, its different to what we have read where submeters have been used for tenants, this is not the case as we do not own the barn or really the meter I guess. There is no MPAN for the meter so we have no idea if it was just stuck in by a mate and/or possibly being bypassed!

Also he is developing on the land so his consumption is likely to increase and may eventually effect our infrastructure. I am waiting on a quote from my sparky to basically dig up the ground (It is split off to him underground) route the main into my fuse panel and then add an additional meter on my side which I can trust and then supply him tails. This would allow us to see the readings easier, be more trustful of it and also allow us to isolate him if required.

We could also set a limit by amperage on his circuit so that if it goes over he trips out. I'm not sure what we would set it at though. If his development increases then so will the usage from this supply meaning the infrastructure might also require upgrading or can we argue that we only supply x amount as that was the original agreement for an agricultural barn?

It did state that we would split the costs for any work but I really don't like the current arrangement and I cant see him being interested in paying for any of this work just so we can keep better tabs on him!

Can anyone see any issue with the work we might have done? or maybe an alternative?

Regards

Mike