I recently heard the expression "Lunchtime Reels" which is well applied when considering the example below. The expression stems from skilled engineers who would look at ways to improve, make iterations and create reels from existing models such as this Silex variation by Hardy Brothers. The analogy can be compared with an artist that doodles in their spare time.
This 4" Silex No 2 variant bears the makers initial initial to the inside "C", for either Clarke or Callow, and features a check mechanism from the 1911 model.
With casting trigger and bridged rim mounted tension adjuster. Note that this is not stamped to the rear.
Of interest is the pillared drum core, drum release latch and the perforations to the faceplate, being different from what we recognise from standard models.
That familiar "C" stamp, being a maker of Silex reels for Hardy pre the 1st World War.
A close up of the pillared drum core.
Note that 5 x dots on both the reel frame and spool showing that these are matched.