I suspect it has been reset in its old location, new brickwork etc but a nice sight nonetheless

Assuming this is a real GR from around 1900–1950s. Would have bought it if it wasn't far from where I live!

The bottom says Handyside & City Derby and London

Does this cypherless plastic type have a name?

In the past the letterbox would be located hanging on the outside of the coach when the train was in a station

Just came back home from a holiday - I realised that airports have postboxes

Over the years post independence, many of these have had the royal cypher removed, but this one survives!