On Sunday, 13 November 2016 10:33:04 UTC, Chris Green wrote:

Which does happen, my daughter got her electricity for nothing for
several years for this reason. She repeatedly tried to find who her
supplier was to no avail. As a result she *didn't* get a huge
backdated bill when it was finally sorted out because only one year's
worth was chargeable.

Yes - the ONLY way I will ever get charged is if BG employ a guy with a torch and clipboard to bang on my door when I am in - not gonna happen.