The red pillar box as we know it today first appeared in the UK in 1857. Prior to this, designs varied from area to area. To begin with these were hexagonal in shape, but were standardised into the cylindrical boxes we know today in 1879.
You can tell in which era a box was constructed as it bears the initials, or 'cypher', of the reigning monarch at the time - eg VR (Queen Victoria 1837-1901), GR (George V 1910-1936), EIIR (Queen Elizabeth II 1952-2022).
In each case the 'R' is Latin for either 'Rex' for a King, or 'Regina' for a Queen.
Pillar boxes manufactured by iron founders Andrew Handyside and Co between 1879 and 1887 omitted the words POST OFFICE and the VR royal cipher, and these boxes are known as Anonymous as a result. The Post Office realised they had made a mistake and made sure from 1887 onwards the royal cypher was included on the pillar box.
However, some rare examples of Anonymous boxes exist, and this is one of them.
At the bottom of the box it states Handyside were based in Derby & A (number of letters).
Use this to take you to the next stage at:
N51 29.(A+1)(A-1)(A+3) W000 10.(A-5)(A)(A-1)
This takes you to another pillar box, this one from the reign of Edward VII (1901-1910), which you will see from the cypher. You may find it interesting comparing this 'normal' one with the last one.
At the bottom of THIS box it states the manufacturer was based in London & B (number of letters).
Use this to take you to the actual cache, which can be found at:
N51 29.(A)(A+2)(A+3) W000 10.(B-6)(B-4)(B-1)
If you are interested in unusual pillar boxes, then check out my other caches in this series:
Special Delivery #1 - GCACP55
Special Delivery #2 - GCAR9WC
Special Delivery #3 - GCARPBA
Special Delivery #4 - GCAVWE1
Special Delivery #5 - GCAXDX6
Special Delivery #6 - GCB4GFY
Special Delivery #7 - GCB118Y
Special Delivery #8 - GCAXE0N
Special Delivery #9 - GCB2ZV0
Special Delivery #10 - GCB359X