Impossible to research anything with no real information.
You still do not provide any markings, in photo or even descriptive form, that tie your gun in with any POLICE organization in Britain.
I do not stalk you.
You happen to post about your Smith on more than one forum I participate in.
You post demonstrably erroneous info regarding your 10-6.
If you have multiple personalities, perhaps you should consult with them next time before asking for duplicative info on your gun, and posting more erroneous guesses about it.
As I told one of you ZVPs in May, I lived in England for two years in the mid-'70s & would be interested in seeing which agency, if any, your Smith might have been associated with.
You never provided any tangible information then to support your assertion then & aren't now.
You say you trust your source, but if he's the same source who told you originally it was a Lend-Lease gun, which it could not possibly be, he shows a marked lack of credibility right there.
You apparently continue to claim it was a British police "loaner", when no such "loans" in that time-frame are known to exist.
That's not the way revolvers were acquired by British police, to the best of my knowledge.
The gun MAY possibly have been owned by an English police agency.
It COULD possibly have been sold by one to whoever your friend bought it from there.
If it does have British proofs, it went through their proof house & indicates it was in that country, but that doesn't make it a police gun in & of itself.
You show no documentation whatever & are unable to provide any POLICE markings for the gun.
As I said earlier- British PROOFMARKS do not support your claim of a gun "loaned" to, or even bought by, British police.
All that aside & even if it was, you (or one of your personalities) knew the 10-6's manufacturing time-frame before you posted your question here about it being the "testbed" for S&W K-Frame .357 Mag origination, and saying you thought the "rumor just may be true".
It wasn't true & one of you ZVPs knew it before you posted it.
Regarding researching the possible police connection, you can do some of it yourself by buying a letter from Jinks at Smith & Wesson that would at least show a part of the trail as far as where it went when it left the maker.
It may have been sold directly to an English importer, which would clear up your "loan" claim right there.
When you post bad info & ask for info you already got from another forum months ago, you shouldn't feel too affronted when somebody points out both.
Denis