Identifying cuffs help

I should be grateful if you would help identify these cuffs. They are marked HARD and W.SANBROOK. I’m not sure if that’s a manufacturer name or police officers name. Any help would be appreciated

William Sanbrook handcuffs have shown up only once before.  You have a rare cuff.

They were discussed in the following entry.
viewtopic.php?p=21232#p21232

Joe

So interesting Joe. Thank you. I can’t find anything online about these cuffs. They came from an Old Bailey barrister friend who had a lot of contacts at Scotland Yard, so I never doubted their authenticity, however as I said before, there’s nothing I can find online concerning this manufacturer. I thought they might be Hiatts. Thanks Joe