Just ran the 465 in 'off the rails' mode on the Isle of Wight and the destination display on the train displayed the correct destination. Cool.
That's interesting! I thought this feature was just on that long wishlist? Or have I not read all the roadmap/patch notes properly...
I don't believe it's been stated on the roadmap either, but this has been a thing roughly since SEHS was released. So far I've seen the 465 and the Javelin being capable of using destinations from other routes, it might be safe to assume every train from this point onwards might be able to support this feature as well!
They said in a stream a while ago that dynamic displays are loco-related and not route-related. So as long as the destinations are saved into a locos system, it will show it.