My parents obtained this little object at the time of the Queen's coronation. I think it was intended to be used in conjunction with the centre page spread of the Radio Times, which showed a map of the route the coach would take, so that listeners (there were few televisions around then) could follow the procession along its route using the model.
The men, the horses, and the coach all separate. I am paranoid about losing a piece!
When I looked in 2016, there were a few of these objects for sale on E-Bay, for a range of prices (search E-Bay for "Coronation Coaches") but not more than a few pounds. You'd think that with the tiny loose pieces, a complete set would be scarce but people must have really taken care of them!
The item appears to have been made by Lesney Moko around the time of, or in time for, the coronation. There seems to have been a Matchbox version, but it looks very similar to me. The web-page shows a number of examples, those with a good original box fetched quite a respectable price.
Below is the Hague and Gray family Coronation Cake, baked with rationed materials, of 1953, which has the coronation coach as part of the decoration.