Spanner in the works

Searching for something small and interesting to blip for Tiny Tuesday I came across this tiny combination spanner set.  It was amongst the things that I inherited from my Aunty, and would have been my Uncle’s.
 
So what is it?
 
Yes, I know, spanners, but what for, and what would their history be.  Google did not help too much other than they seem to be a ‘Motor Bike Magneto Spanner Set’ of some sort, but I could not find one like that with the set screwed together.  Even Googling the number Rd No 693631 did not unearth a clue.
 
So are there any ancient motor bike enthusiasts out there that can throw a light on this (hint hint)?
 
Many thanks to Carol for hosting Tiny Tuesday this month.

Tec bits for those interested:

Blip photo - three shot focus stack
Spanners laid out - four shot focus stack
Work in PS Elements 11 with Elements +




ps - Kipsie has come up trumps straight off