CCCWC May competition voters’ comments on Clue no. 6

A clue to MICKEY.
3 comments refer to this clue (from 2 competitors, 1 other)

Here is the text

Comments on the clue

1.	I couldn't find any evidence for the def.
2.	Neat but definition too obscure
3.	"Unit" feels a bit vague as a definition for a specialist piece of knowledge (not in Chambers, for example). Neat construction though!