I’ve had a really negative experience with Eurostar.
I tried to book a Standard Premium seat reservation, but got an error. I was told I could not book that with my Eurail second class pass. Nowhere was it specified that this was the case; in fact, they offered me to upgrade from the Standard res! Deceptive. I changed plans and STILL could not book my reservation. As a solo traveler, if I cannot book on mobile, Eurostar’s service is absolutely useless and shameful. I’m extremely disappointed in these operators.
Further, I’ve already ridden on a Eurostar train two days ago and I felt it was pretentious, overpriced, and a hassle.
PLAN IN ADVANCE AND BUY AN AIRPLANE TICKET TO THE UK INSTEAD.