Looking at this post box, with your new knowledge on postboxes from the previous stop, which monarch was on the throne when this post box installed?
Edward VIII.
Therefore what one year can it be dated to?
1936!
As a town, Dunfermline has two unusual references to the year that Great Britain was ruled by three kings, 1936. There is one building and this post box which evidence that King Edward VIII was on the throne long enough to be recognised in architecture and social infrastructure before abdicating. His coronation was scheduled for May 1937 but he abdicated in December 1936. There are thought to be only 57 postboxes with this identifying mark in the UK, out of over 100,000 total postboxes, surely making this quite unusual!
More unusual is the building on Guildhall St which has his initials in the stonework and represents a (former) public building Labour Exchange, built during his short reign. It’s marked on the map if you want to have a look when you get back to the Mercat Cross, it is within 25 steps to the south of the Cross.