Bryan Morris wrote:

really - how many hgibe their address as Bromley Kent - I suspect that
Bromley at least think themselves as part of Kent not London

I'm in Loughton Essex, on the tube & most buses are red. Until fairly
recently the Police were Met (now Essex)

Ilford & Romford are nominally Essex for Post Code purposes and most
people assume they are in Essex but in fact they are in London Boroughs

The postal counties were only abolished in 1996 so there was a generation
plus who lived in London but still had to give their address as "Kent" or
"Essex" or "Middlesex" or "Surrey" or "Hertfordshire". The 1996 abolition
wasn't well publicised, plus a lot of online forms force a county onto
addresses (I've often had to use the nonsense of "London, London"!) so these
old locations persist.

Although this wouldn't have been a certainty - see the history of
Humberside - it's probably that if Royal Mail had updated postal addresses
in the 1960s then we wouldn't be having this discussion. Perhaps it would
have happened if Tony Benn had had better priorities than trying to remove
the Queen's head from stamps.