thanks for the reply! I haven't no however I paid a penalty fare to Arriva in 2016 when I lived in student accommodation in Leeds. This notice has my address on so I'm not sure why I wouldn't have received the other two reminded letters.

Hi everyone, At the end of last year I boarded a train without obtaining a ticket or a promise to pay notice (I didn't have time as the train was about to leave the station) and was therefore issued a penalty notice which I subsequently appealed in the coming days. Since receiving an email on the 6th of January confirming my appeal I received no correspondence from Arriva or the penalty service to which I appealed about the result of said appeal today when I received a Single Justice Procedure Notice with a settlement offer of £100 before prosecution. The notice claims the appeal was denied and two further reminder letters were sent but I am certain that I DID NOT receive said letters. It's possible I might have missed one letter but not two. If I were made aware of the result of my appeal I would have just paid the initial fine of £20. Obviously, this is just my word and I can't prove whether I received a letter or not so aside from paying the fine or contacting the citizens advice bureau I'm not sure what to do. Any advice would be massively appreciated, Thanks