North Lincoln (10th Foot) Regiment Silver Plated Large Pattern Button - Mess Orderly / Waiter?

Circa 26mm in diameter, fixed shank, maker marked Firmin & Sons Ltd, London. Silver plate dark toned, some wear to plate on high points, but an attractive button in very good condition. Unable to confirm this pattern to Regiment so suspect it is a mess waiter's button. Any information welcome.Comm DaSm