Terry "Quins" spanner

Note the fact that the spanner has a 5/32nd Whitworth size!  I've found this once before on a Triumph wrench:

British Tools and Fasteners has a webpage with a table showing all of the BSW sizes, which include 3/32, 5/32 and 7/32nd sizes.  The 5/32nd size is the only one in the series with 32 threads per inch.

Also see Mister G's posting on Herbert Terry & Sons.