Unusual Plug '8' handcuffs

One of my recent additions is a rather unusual Plug '8' handcuff. Initially I did not take a great deal of notice but now having examined it closely see it is quite different to the standard Hiatt or Froggatt plug cuffs normally found. You will notice that the barrel is almost half way up the cuff and the key (I assume to be the original) is small and unusual in shape. The hole where the plug (which is not present) has a much wider diameter than any other plug cuffs I have seen.
The scan shows this and can be compared against the standard plug cuff also shown. I would be interested to hear if anyone has a cuff similar and especially if it has a makers name on it - mine has been lost in time.

Chris

I have about dozen plug 8 cuffs, but I have never seen another like this new one of yours. It is very neat.

Joe