Not sure if this has been discussed in another thread, but if you buy tickets for two or more people travelling together and opt for e-tickets, are they issued as one e-ticket for the entire group or as separate e-tickets for each person?
If they are issued as separate e-tickets for each person, presenting them for inspection will obviously be more of a faff, and even more so when passing through ticket gates if the journey starts and/or finishes at a gated station.
If you bought the tickets in a single transaction (which you have to do if you are using a Family & Friends, Two Together or Network Railcard) and using a train operator's app or other ticketing app such as Trainline, you can presumably open the app and retrieve all the tickets for the relevant leg of the journey in one go, though if you have your railcard issued as a digital railcard in a separate app you still have to show that separately (and if you have bought a First Class upgrade using the Seatfrog app, that's a third app that you have to open during a ticket check!).
Obviously one way round the problem, if the tickets are issued as separate e-tickets, is to email each person their ticket for them to show as an attachment on their phone, as long as each person in your group has an internet-enabled smartphone.