How the heck do I track down my energy supplier?

[Florence4170]

I have rented out a property for many years but am now selling it. It became empty in October and since then I haven’t had an electricity bill. The last tenant passed away so I can’t ask them! I have spent ages looking online to try to find out but although I can identify the people who look after the lines etc but I can’t work out how to find the supplier.i was content to wait until after Christmas to see if a bill came in but the buyers want an answer. I obviously do need to know, to effect a handover!
in e contacted Octopusand Eon. Impossible to get through to British Gas, Ovo, Scottish Power without an account.
i don’t know where to go from here. Any ideas gratefully received please!

Would the last tenant have a paper copy of the bills?

https://supplier.nationalgrid.co.uk/Home/IndexM

I had this when I moved in somewhere and had no paperwork. I just called British gas and asked them if I was a customer. I wasn't, but they were able to say who I was with.

https://www.ofgem.gov.uk/information-consumers/energy-advice-households/finding-your-energy-supplier-or-network-operator is this any help?

https://www.ofgem.gov.uk/information-consumers/energy-advice-households/finding-your-energy-supplier-or-network-operator

Have you followed those steps?

Your network operator can tell you who your supplier is - details

Sorry for being the third one to post!

Thanks so much!