Thank you so much for your assistance. With a little more research just now - and help from Google AI - it appears this may be a commemorative medal (1887 or 1897) made with a blank reverse side specifically so that the recipient's name, the issuing organisation (such as a local government or school), or a specific message could be engraved later. This added a layer of personalisation that mass-produced, double-sided medals did not offer. These medals were produced by various private mints using different techniques. Not obvious in the photo but in my item, the bust has a silver wash/plating applied giving it a unique characteristic. Again, thanks for your help - it pushed me to research more.