In my experience, most electric in the whole of UK, regardless of location is 10p per KW or more.  You can get day/night rates of, for example, 13p and 9p - but unless you've got a wind turbine of your own, or huge solar farm then you can't get it much very cheap.

I would love to be proven wrong if anyone has information to the contrary!  Plus I'm talking 100,000+ KW per year, not residential rates.