The hallmarks have date letters, these change each year, 2023 was "Y" this year 2024 is "Z" next year it will be a different design font and start at "A" again for 2025, then 2026 will be "B" and so on and so on, its so you can date which year it was hallmarked / made.
@@SerpentSilver They go higher and lower case as well, the assay office was started in 31 August 1773 so been going ok since then :) some do look similar but normally they are 100s of years a part and you can tell by the style of the piece if there is confusion