The date of a cancel aids in identifying a stamp, as it often indicates a period of use. This was a commemorative machine cancel which coincided with the issue of the Jubilee stamps in 1897, close to the end of the Small Queen era. Thus, even without stamp in hand, it's 99.9% likely a 41.
The BNAPS flag cancel study group is dormant but it's a fun collecting area and someone is bound to revive it someday. Their newsletter archive is freely available online for any interested to read:
https://bnaps.org/hhl/n-flags.htmAdditionally there are reference books, for those interested in a deep dive into the subject, available from BNAPS booksellers at modest prices.