Must be Arthur Hebden of Bretts, Judiest & Hebden (sometimes written Hibden), or plain Hebden & Co, army clothiers and suppliers, Parliament Street (or sometimes Parliament Square), London. Don't know much about the firm, but you come across the name in connection with contracts for clothing, accoutrements, knapsacks etc. Don't know if they did bespoke stuff for officers.
But, interestingly, it appears that "Mr Hebden the army clothier" was implicated in the massive and complicated scandal involving the Duke of York, his ex-mistress Mrs Clarke, corruption in the army, etc etc; Hebden was alleged to have received part of a 1000 pay off in connection with the paymastership of a battalion of the King's German Legion, and admitted to selling other commissions.
Not sure how he came to be in a position to do this, and I can't offhand find anything confirming that he was clothier to the KGL, but it seems a good bet.