Hello
If silver plated it is more than likely an officer's button which might explain how it found its way here to the UK.
Poulsom gives the uniform lace details for this Regiment as follows "1798 Silver, 1807 Gold, 1809 Silver, 1818 Gold". Silver lace usually means silver buttons to match (I'm sure there are exceptions to this though!) so you can narrow the date of your button down a bit, most likely before 1818 and possibly as early as 1798!
Interesting to see the back but I can't make out the backmark. Is it clear enough for you to read?
Roger
|