Thank you for sharing that link to our original STEN bayonets.
We actually have a couple of variations on the markings.
Its fortunate that I have an interest in the STEN, we sourced original bayonets and later identified MK5's that were made in Pakistan in the late 1960's (that is NOT documented in the STEN books)
Then they bought BSA's production line for the #4 rifle, they also acquired the STEN MK5 machinery.