Royal Regiment of Artillery, early 19th century GR, officer’s 20mm

Georgian period button with the title ROYAL REGT. OF ARTILLERY on a garter with cypher GR within and a Georgian crown above.  The 20mm officer’s button is open backed and rather domed, with the visible area of the backmark reading DOLAN & SON, LONDON. The button is in better than average condition with just a little rubbing on the high points of the design but it would benefit from a clean. There is possibly something before the D of the maker but it is obscured by the original fixing of the shank.   feb7/1. SOLD 27th February 2023