Generally the Uk proofs for farthings and other denominations unless stated as a commemorative proof will be in the handfuls and made for V.I.P diganatories The proofs unlike the standard strikes are struck on specially prepared blanks usually polished before the strike to give a mirrored finish in contrast the subject and all the lettering will be struck unpolished to give the cameo effect we normally see on proof coins although sometimes it is difficult to see the cameo.
Also proof coins are struck at least twice to make sure that everything is well defined and no weakness shows in any part of the design unlike a standard coin which is struck only once . Such coins the ones not in a commemorative year are like hens teeth and the only way you would come across one of the is if someone who was handed down such a coin and knew nothing about coins and put it up for sale without knowing what it was and the chances of that are probably the same as winning the lottery :)
Also proof coins are struck at least twice to make sure that everything is well defined and no weakness shows in any part of the design unlike a standard coin which is struck only once . Such coins the ones not in a commemorative year are like hens teeth and the only way you would come across one of the is if someone who was handed down such a coin and knew nothing about coins and put it up for sale without knowing what it was and the chances of that are probably the same as winning the lottery :)