Are al these "units" the same - only with pints and gallons Anerican ones are smaller, so it never does to assume anything. (And there are always things like metrication to take into account.)

I looked at some bills which are a couple of years out of date, and they gives it as 1.413 pence per kWh for gas, and for electricity bill it's 6.13 per unit.

I think life is too complicated to get into these deals with the gas people supplying the electricity and the telephone people supplying the gas, and the milkman delivering coal and so forth. I assume there are enough people charging around after the best deal to put enough competitive pressures on the companies involved, and it'll all work out much the same at the end of the day. So I'll stick with people doing what they are there to do.