I think my problem arose in that the date for the supply starting from british gas was staggered for the electricity and the gas despite being on Dual Fuel. The electricity was two weeks after i moved in and the gas 4 weeks. I supplied meter readings to british gas for both utilities on the relevant start dates but given i have used not a single unit of gas i am loathed to pay for the standing charge...
I think the key point is as you say "in the abscence of a supply agreement" which means i am likely obliged to pay despite never signing up to their standard rate with standing charges. With heindsight i should have checked who the default supplier was and asked for the best tariff from them before being landed with the final bill.
I know for next time to question everything including the default supplier should my prefered choice not be connected in time. It is disapointing British Gas just told me they will sort everything and I don't have to lift a finger...
Time to call Scottish power and see where i get to.
Thanks