Railcard Rules.
Railcard holders traveling on a discounted ticket must carry their Railcard when they travel. If a Railcard holder fails to produce a valid Railcard with their ticket, a new ticket must be purchased as if no Railcard and/or no ticket were held. Going to see our daughter this weekend on the train, I had that sinking feeling when the taxi dropped us off at the train station and I had realised that I had not got my plastic railcard with me as it was still in my desk at home

With six different train journeys to make on different trains (there and back) it could be very expensive with having to buy full fare tickets with maybe a fine.

So my plan was to get on the train, get a seat for my wife and I.
Then go to look for the 'Train Manager' (Guard)
Do Not wait for them come to you !.
On your phone log on to your 'Railcard Account' , it will show that you have a valid railcard.
Have your tickets with you.
Show the train manager your tickets, then show them your Railcard account and point out that you have a valid up to date railcard, say sorry that you have left it at home, ask them if they are happy for you to stop on there train and use your tickets (Remembering That They Are In Charge Of The Train (Not the driver)
.Be pleasant and nice to them.
I did this on each of my trains and it worked each time.
I got a way with any extra fares or fines.
If possible speak to them away from other people ( I spoke to them in the gangway ends of the carriage in private ).
I remembered this advice a train manager gave me some years ago, if you have any problem go and look for them and talk to them, they appreciate you going to them and asking there advice.
I did a similar thing last year, flying back from Amsterdam the plane was very late and we missed the train we were booked on, so got on a later train, I went to see the train manager and showed him our tickets from the earlier train we missed and told him what had happened and asked if he was happy for us to uses this train, He said take a seat and enjoy your journey.
I hope this advice will be useful to someone .