That button has some great maker's marks. Very nice 👌IMO, Creskol got the country-of-manufacture (the "Lion Passant" in the backmark is a British hallmark) and the date-range exactly right.
Technically, brass 1-piece flatbuttons with an indented-lettering backmark (like yours) can date as early as about 1810. But the war-of-1812 and postwar boycotting of British-made goods means it's very unlikely that your British-made button arrived in the US before 1820. Therefore, I agree with Creskol's 182030 dating of it.