Help identifying markings on a silver fork

Hi could someone please help identify what these markings are on this silver fork? Thanks in advance :slight_smile:

The markings show that the fork was made by James Dixon & Sons of Sheffield and that it is not silver as these are marks used by Dixons on electroplate. As far as I know we have no explanation for the additional marks, “57” in the lozenge and “3” in a circle.