The groat is a fourpence coin. Circulation issue groats (like this one) had the Britannia reverse; Maundy Groats did not.
1847 fourpence coins are only listed as 1847/6 (overdate only). Remick's Guide and Catalogue of British Commonwealth Coins 1971 does not list mintage for them but says they are "extremely rare".
Head of Queen Victoria facing left, ribbon in hair; around, VICTORIA D: G: BRITANNIAR: REGINA F: D:.
Figure of Britannia, draped and wearing helmet, seated facing right holding trident and resting right hand on an oval shield which bears the crosses of the Union flag; around, FOUR PENCE; in exergue, the date 1847.