No provided documentation - now what?

[krty]

Last Monday I was traveling from st Pancras to Rochester Southeastern high speed with a 16-25 railcard discounted ticket but didn't have a valid railcard with me.
*(The one I have in my phone was expired one week before when I had a week off from uni that's why I took that time to order my Santander railcard which I was still waiting to arrive)*
When I arrived to Rochester there were a lot of Southeastern staff and police and got asked for my railcard and obviously couldn't show it.
I told them I didn't have mine with me, tell them my name and address, pay a penalty fare (£43) and they gave me the penalty fare notice.
I thought that was all, but I decided to make a little research and I have read that they can prosecute you for that!
So my question is, now what? Will I receive any letter? Will they ask for my side of the history? Will they ask for more money? I'm going to be prosecuted??
This situation is confusing and stressfull.

All advice is welcome.
Thank you in advance.

 

[island]

Did you pay the penalty fare? If it has been paid, then that is the end of the matter and no prosecution will follow.

 

[najaB]

I told them I didn't have mine with me, tell them my name and address, pay a penalty fare (£43) and they gave me the penalty fare notice.

As @island noted, provided you paid then they won't prosecute.

 

[gray1404]

You will have been given a receipt for the penalty fare right? Has your new railcard arrived in the post yet? If the new railcard was valid on your date of travel but you just hadn't received it yet in the post, there is a possibility the train company may treat this as a forgotten railcard case and refund you. However, strickly speaking you should not be using railcard discounted tickets until you have received your new railcard.

What is the expiry date of your new railcard?