The "Junior" was the second in size of SEL's range of stationary engines. It has much in common with the "Major" (like the gold painted brasswork and the same high quality workmanship) but is simpler. It has only one cylinder which is mounted on a simple bare metal (aluminium?) bracket and it has no lubricator or whistle. The meths burner is similar in style but has only one wick.
This example has the slightly less common red base. It is a combination of parts from two engines, using the best from each.
I have a copy of an original "Merit" catalogue containing this engine and I quote:
"JUNIOR" STEAM ENGINE No. 1530
As befits a traditional British product, all the dimensions are in imperial units - except the boiler capacity, which is in metric! I wonder why. The bottom picture on the left is taken from this catalogue.