It's because of the electric plugs you use. If you have a two pin plug on your appliances you will obviously use more electricity per pin than a three pin plug. So expect your bill to be higher - simple as.
hi John, i had just put my handbag away - the new passports say British Passport, the UK government website calls them British Passports, the consulates all them British Passports. Your passport, although still legal (guessing) is a legacy of the pre-Brexit times.