Paul

It was to do with having "multiple meter points" in a property, something the vast majority of people do not have.
They were getting multiple standing charges (allowed) but this took many of them over the price cap (not allowed).

Octopus had the largest number of affected accounts, but it also affected Utility Warehouse, Ovo Energy, So Energy, Outfox The Market, Ecotricity, E.On Next, Tru Energy, Rebel Energy and EDF Energy. As best I can tell, all should already have got their payments by now.