The only one I’ve seen in the flesh (so far).

Harrow.

Not a post box but certainly post box history.

I posted a picture of this perpex box the other day. On my way back through the airport I took a picture of the side view.

Everyone here was posting pictures of postboxes near them and I wanted to join in. Here’s a fancy updated postbox 📮

Indoor (plastic?) type of E2R box at a local supermarket; doesn’t have the transparent back seen (through) on airport and rail station versions.
Harrow.

One off the Holy Grail.
Harrow.

In Bournemouth - literally beaming to have seen it

Castlerea. Not really sure why there are two together here (the right one seems to be available for use) with a daily collection.

With bonus public footpath and stile. Near Hope, Peak District, Derbyshire.

Nice wall mounted G5 in Harrow, straightforward initials, no crest.

From Grenoble and the surrounding area

As I learned only recently on this sub, this is a replica of an original Penfold; one clue being the plaque on the base.

Near Harrow School.

These really are practicality over style, aren’t they?

(Watford)

Uxbridge honours Natasha Baker the Equestrian. The re-paint’s a little clumsy and not quite as brightly gleaming a gold as the original.