I understand how the energy market works @SerendipityJane
(although I think we'd both agree about the short sightedness of the Conservative government allowing the main gas storage facilities, which would have helped smooth out some of the peaks and troughs, to shut down
)
But how does that explain the difference in standing charge across the UK: 64.17p/day in Southern Scotland (which is what I have to pay) versus 41.59/day in London?
If it's purely based on international energy markets, then Ofgem should have the same cap on prices across the UK. 
I can understand why the people in the North of Scotland are extremely pissed off that they are having enormous wind farms built around them, interconnects (with giant pylons) being built across their countryside, to transfer the energy to England (iirc, in simplistic terms, SSE and ScottishPower have to pay to put money into the National Grid, because it's calculated on where "most" of it will be used), yet have to pay more for their energy. 
So they are triply penalised: live in a cold area, so have to heat more (and can't use gas); have to thole wind farms and giant pylons around them for the record, I'm not against wind farms ; and Ofgem sets a higher cap making them pay more for their energy 

