4700 stamped on arm  so i believe this to be the long reach version  47 to 57mm, i have also shown in the pics  the distance from centre bolt to approx centre of brake shoe slot.

 The Superbe logo is stamped in, this indcates it an  earlier version of the caliper.

   

 Brake shoes have been opened at one end to allow the fitting of replacement  Kool Stop Salmon pads (unused).

 The curved washers are not original  but all other nuts/bolts  look original to me and are in very good condition as are the chromed parts