- I have someone with the same first name and same last name at the same house number on the adjacent street.

- There is another street with the same name in the same city (although it is a different postcode).

- There was someone with the same surname and first initial in another flat in my block.

On that last point, it has been a particular bone of contention that the Post Office insist on identical postal addresses in their Postcode Address File (PAF) for different flats which share the same letter box. I always specify my flat number where I can to ensure I am uniquely identified (which is important for identity documents, financial information, insurance etc.), but in systems which use the PAF with no manual override I can't, which has led to all sorts of issues over the years, e.g.

- Unable to transfer an ISA because my old and new details didn't match.

- Had a former neighbour successfully set up a postal redirect for all flats in the block not just their own, meaning all my post, including bills, bank statements, a renewed driving licence which I happened to apply for at the time, basically everything you'd need for comprehensive identity theft, was redirected to someone else for several months with no-one able to do anything about it.

Apparently the only (absurd) workaround to get a unique entry in the PAF would be to physically install another letterbox in the same door (leading to the same floor).