According to Simon Barley in "*British Saws and Saw Makers from c1660*" at
page 85:

"*With time, the elegant medallion became as sadly debased as several other
design features of saws, including the blind medallion (Figure 4.39). The
change was gradual, with simplified designs appearing between the wars.  A
particularly marked decline is seen in the last two (Figures 4.40 and
4.41).*"

where I am sorry to say that Figure 4.41 is a Spear and Jackson medallion
similar to yours but with the word SHEFFIELD on the outer rim between the
start and end of the two rings of writing.

The medallion is said to date from "*c1950*".

best wishes,

Mike.