The Meter Point Number Helpline is 0870 608 1524 and they will help you to find your current supplier.
It is quite possible that you will be asked to pay on a more expensive tariff than you want, perhaps with a high standing charge. There are rules on how far back they can bill for a standing charge though.
I am using commercial premises and have just received a bill of £1300 for using just 800 units. Most of this is a £1.45 per day standing charge. I am, of course, arguing with this tariff. I doubt that such a tariff could be applied to a residential supply but I am not sure.
When you move into premises, it is your responsibility to find out who the supplier is and put the supply into your name. In my case, I was incorrectly told that the landlord would bill me.
Unless you are planning to move in the near future, you should try sort the matter out soon.