What the heck - am I some sort of clot or something?

Most of this told you some while ago here - I say most, referring to the parts that bear a semblance to accuracy rather than fancy.

He was not from Scotland, being born in Sheffield - as I already told you/
He is on record in 1810. Besides, how can he first have showed up in Edinburgh when copious records already show him in Glasgow at a much earlier date?
'Messrs' is an abbreviation meaning simply 'misters' - there is no such thing as Messrs & Son. If I formed a company with someone called Johnson we would be Messrs Miller & Johnson. Get your facts straight!
Hilliard (Harvey) would have made surgical instruments, having been appointed as Surgical Instrument Maker & Cutler to the Queen. Damnedest coincidence, what?!
Census records I have read show that his son Frederick was his assistant (ie apprenticed to him) by at least 1871 and had gained his Freedom by 1881. Your razor only has the fathers name on it. The name was changed to Hilliard & Son when his son joined him, so the razor is from before 1881 - but I told you this already. So, your dating is erroneous.
Jean Jacques Perret in his seminal book L'Art du Coutelier dated 1771 shows a multitude of hollow grinds, making Doyle's statement a little unreliable at the best - being charitable, here!

If you don't pay any attention to FACTS what's the point in trying to educate you? Sheesh, as far as your future enquiries about razors are concerned than count me out.

As Guitstik would have it - 'Thanks a Freaking lot'.