BSW Filler Plug Armstrong Rear Shocks?

[twas_brillig]

The filler plugs on the rear shocks didn't seem to match Imperial or Metric wrenches last night - bigger than 1/2 inch; too small for 9/16; bigger than 13 mm etc. I've got one socket set where the socket design allows them to used on both metric & imperial, and successfully used the 14 mm. Any advice as to the sizing? Possibly British Standard Whitworth?

 

[Bayless]

Try this adjustable spanner :highly_amused:

 

[twas_brillig]

normally I just grab the nut twixt thumb and forefinger....... Doug