NPower meter confusion

watchingmymoney

Hi, my apologies for the long note but it is a bit complicated......
I was told in November 2010, after my landlord had new meters installed in a common area that is now accessible to everyone (he built a new flat and office, replacing the larger single office, under my flat last year and had to put in these new meters as a result) that the "old" meter, the meter that had been way up above the doorway entrance into the building (and hence not accessible) was my meter and that I was with NPower and not EDF as he had told me I was when I moved in.
When I moved in over 3 years ago I was told (via letter) by the landlord that my supplier was EDF and that there was no meter for my flat and he would arrange it (he had converted 1 large flat which was above the office into 2 flats). A couple of months later I got a letter from EDF networks (address to the occupant but with the correct address: to the first floor flat which is mine) saying that they had to do some work on the office below my flat and my power supply would be affected as it was looped into the office below. This was in line with what my landlord had told me; that my flat was looped into the officed as well.The LL also told me that the old meter was for the flat upstairs from me.
It now seems, as of November 2010, that the old meter belongs to my flat. I have since called Npower several times to clarify whose meter is whose in the common area. I have said I am happy to pay from my being informed that they were my supplier in November 2010 until I move out (due to move in March as LL gave me notice last month after the building works downstairs were completed). I have also called EDF to confirm the meter registrations and whether or not I am with them. EDF now say I am not and initially NPower said I was not (I've now called them at least 3 times and they have finally given me a reference number). As I don't want to give my LL any excuse to withhold my deposit I called NPower again today to be certain that I get my bill from November 2010 until I leave in March.

The thing is, I am afraid they will try to make me responsible for a huge bill (over £1000) that dates back to when there was just 1 flat (referred to as Top floor flat). A bill was sent addressed to the Top Floor Flat in December 2010 without a meter number listed in the bill and my upstairs neighbours opened it but said it wasn't theirs and so handed it to me. That single top floor flat was demolished in 2006 to make way for the first floor flat (my flat) and the 2nd&3rd floor flat (my upstair neighbours). I don't know if that bill dates back to that time, if it includes all the electricity used by the builders in 2006/07 (when my flat and the flat above me were built) as well as by builders in 2010 (when the new flat and smaller office downstairs were built). I don't know if it includes common area (lighting) electricity usuage as well.
My concern is that Npower will try to stick me with this bill, claiming that the meter was always mine (as I said I was only told by the LL in November 2010 that the NPower meter was mine, I did not have a meter number prior to this as the LL never had one put in as he said he would and I did contact him several times about it in the first few months then gave up). Npower never contacted me (as the occupant of the first floor flat) at all during the entire time I've lived here (although EDF did). I don't know if it the old meter was for my flat all along or if it is just simply a result of all the re-metering. I am willing to pay for the electricity that I used but it doesn't seem right that Npower might try to charge me beyond that.
Any help or suggestions welcome.