A favourite topic among Numista members, I decided to do some research and found the following:
The Gothic style crown was issued only in 1847 and 1853. Edge inscriptions (in raised letters) refer to the year of reign. The extremely rare pieces dated 1847 with SEPTIMO on the edge are all proofs and are either errors or trial pieces struck in 1853 with the old reverse. The proof crowns dated 1853 were included in the sets but were not issued for circulation. The obverse was designed by W. Wyon and the reverse by W. Dyce.
1847 UNDECIMO................... 8,000 minted
1847 SEPTIMO.................Proof only
1847 Plain edge. ................Proof only
1853 SEPTIMO, ......................460 minted
1853 Plain edge. ................Proof only in sets
I think the coin sheet (https://en.numista.com/catalogue/pieces23740.html) may benefit from a little amending.
Ref: "A Guide Book of English Coins" by K E Bressett, sixth edition, published by Whitman, 1967

