Hi I am currently planning some wiring modifications for the two flats
in a building I own. One flat on the ground floor and one is on the
first floor.

I plan to have the ground floor flat supplied directly from the
original elec board's power supply meter for the building. I plan to
have a submain coming from that to the first floor flat, going via a
payment meter of some kind (coin or card perhaps). My plan is that the
occupier of the ground floor flat will be responsible for paying the
elecricity bills for the whole building, while the occupant of the
first floor flat will either:

A) Pay for his electricity via a coin meter to which the ground floor
occupant has the key and has the right to collect the coins at regular
intervals.

or:
B) Pays for his electric via a card meter, buying cards from the
electric supply company, so that when he buys the cards, the amount
paid will be credited to the ground floor flat resident's account. Is
that feasable, and if so, would it be simpler/better than using a coin
meter? How much do the supply companies typically charge to install
such a meter?

Are there any other possible options? I do not want to go to the
expense of having a second mains supply installed for the first floor
flat by the supply co just yet. However, I may well decide to, in a
year or two, if (a) or (b) above proves problematic/inconvenient for
any reason.

Thank you,

Frank.