Originally Posted by
DL116
I've done it twice within the last month - in both cases the staff on the train showed us where to find free seats on the train. Was no problem at all & the XP also swiftly found their way to my account

can confirm, Eurostar staff is very lenient. Earlier train was full, but they let me use a folding chair close to the doors anyway. Saved me from 2 hours wandering around in Shithol. Friend of mine also managed to take an earlier train the same afternoon - did have a seat though.