There is a Guardian consumer article about a case where a company has gone to court for nonpayment and is about to break down our door and install a new meter, which included a warrant. This was a result of a mistake, after which someone started getting bills to an unknown person. These were returned, presumably following the Royal Mail instructions for such a situations.

I do not know really how I works, but I assume these "bills" included some legally information regarding the issuing of a warrant such that if the company had broken down the door and installed a new meter without sending the letters it would be illegal, possibly breaking and entering. What is the legal situation when such preformative letters are sent but returned unopened with 'Not known at this address' on the envelope?

There is a Guardian consumer article about a case where a company has gone to court for nonpayment and is about to break down the door and install a new meter, which included a warrant. This was a result of a mistake, after which someone started getting bills to an unknown person. These were returned, presumably following the Royal Mail instructions for such a situations.

I do not know really how I works, but I assume these "bills" included some legally information regarding the issuing of a warrant such that if the company had broken down the door and installed a new meter without sending the letters it would be illegal, possibly breaking and entering. What is the legal situation when such preformative letters are sent but returned unopened with 'Not known at this address' on the envelope?