Don't discount the officers of the East India Company and the Volunteers raised and stationed in Great Britain during the Napoleonic wars.
Great Britain had a huge number of men under arms during this period who weren't restricted to the regular army supply chains or regulations. Many wealthy businessmen raised and self-funded volunteer or yeomanry companies that did little more than parade on the weekends to impress the girls. Looking at the period art, there is quite a variation from regulation in both the uniforms and swords carried.
Light Cavalry Officers 1806
London's Volunteer corps 1799
(note the sabres with steel and gilt hilts, and two of the soldiers look to have the 'flank company' shoulder boards.)
Loyal Volunteers on Parade 1803
(the three officers carry spadroons that look like the 1796 Pattern while the fourth on the left has a sabre in a leather scabbard).