In that case would they be bound by them?
How do rights and responsibilities get transferred to subsequent parties without their knowledge?
Covenants etc are in the deeds when property is bought/sold, but if it's just a standalone agreement between A & B, can that become an agreement between A & C without C knowing?
Yes this is exactly why I say it's tricky, for example my neighbours and I have a verbal agreement over outdoor sockets, in the event of losing a phase from the sub to run an extension lead for essentials to the others socket, if either of us sells would we think to mention it, equally we have adjacent drives, the neighbour has extended and left only a couple of feet of theirs, it was he who suggested I parked further over.
Okay I accept they are tiny points in comparison to fixed wiring. The point with the thread is; there is a paragraph in the lease about sharing the cost of the bin store lighting but I am under the impression that was never claimed (if it really is only pennies per year I wouldn't bother asking for reimbursement either) but somewhere along the history the use of the afixed building has changed from a garage to a workshop which the tenants are aware of but if the original owner wasn't switched on to the increased energy usage and let it ride, then I can fully understand how the bad situation arose.
As to if there is a written agreement between A&B and that wasn't disclosed to C (deliberately or accidentally) may very well be grounds for a legal arguement, many boundry disputes spring from there.
For example: My sister has an agreement with their neighbour, between their garages is an area which had been simply lawn for years:
but the boundry is the centre of the road.
Wanting somewhere to park a motorhome they asked if they could purchase enough land to fit in a hard standing for it but the neighbour didn't want to get into any sort of legality and insisted they just do it, not having a motorhome anymore they have now turned it into a flowerborder but no written agreement anywhere. If my sister were to sell I'm sure the buyer would expect the hard standing to be included if not otherwise mentioned
Although as JohnW2 says, if it's rented properties, interfering with the electrical installation might be a violation.
I have every agreement with that expectation and I have had to reinstate the damage caused several times.
But then if there's nothing in Cs tenancy agreement which says he has to pay A, or he has to supply A.....
As mentioned it is tricky if that arrangement has been in place for a while, some things aquire legal status after a predetermined time and I have no idea if that is one of them.