This thread has become quite difficult to follow because edits have been made to posts causing them to disappeaer from public view until they are approved by the moderating team and also because what has happened has been 'drip fed'.
I've read through the whole thread and this is what I think has happened:
- In September you were caught travelling with railcard discounted ticket but your railcard had expired in June
- Your details were taken
- At times in the past you've bought Senior railcard discounted tickets for journeys you've made yourself
- You've since renewed your 26-30 railcard
- Chiltern have researched your ticket purchasing history and have written to you, saying that they are considering prosecuting you but asking for your version of events before they decide how to proceed
Chiltern are entitled to prosecute you if they want to but normally they will offer an out of court settlement to people who co-operate with their investigation, and who haven't come to their attention before. Expect to have to pay the cost of all the fares avoided at the full Anytime rate with no credit given for invalid tickets you did purchase (i.e. all of the senior railcard tickets purchased as well as the 26-30 railcard discounted tickets purchased when this railcard was out of date). In addition you will have to pay an admin fee, typically around £150.
The draft letter along with the amendments suggested by
@Wethebest838 is fine but you do need to address the other occasions where you have travelled with invalid tickets. I suggest you carry out your own research of your ticket purchase history in your Trainline account and say something like:
I have checked my Trainline ticket purchase history and believe that between ddyymm and ddyymm I have purchased xx tickets with an incorrectly applied Senior Railcard discount and yy occasions where my 26-30 Railcard was expired.
You mention using a solicitor, only you can decide if this is something you want to do. My own view is there is no need to use a solicitor at this stage, they aren't cheap and they cannot change what has happened. What they can do is present your mitigation in a better way than you feel able to do yourself but my vuew is the facts in this case are straightforward (however uncomfortable they might feel to you!). I would send the letter to Chilten witht he suggested amendments and if Chiltern do not offer a settlement then that is when I would consider using the services of a solicitor.
Do post an amended draft of your reply in this thread so that we can proof read it. It's also very late as I write this so I think we should all take a step back, sleep on it and review things in the morning.