Technically i believe unless you are sitting in prioity seating (which is an offense not to vacate if requested, as it is normally near a door), a concession card traveller only has to vacate their seat if there are no other seats avaliable. If there was any other seat on the train i would have told them to go and seat there, it's her problem if she can't sit near her friend.

And as for her other behaviour, it is just appalling, and i know she won't be, but i hope that she reads this website, and is damn right embarressed by her behaviour.. shows a lot more about her and her self control, along with upbringing, if thats how she thinks people behave.