Should we be compensated if Eurostar downgraded us?

Q My wife and I were booked on Eurostar Plus from Paris to London. Our train was cancelled.

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We were given two choices: going on a waiting list for the next departure or a guaranteed seat on a train five hours later. We chose the waiting list option, went through security, then spent a worrying period wondering if we would be successful or not. Finally, we were given standard class tickets, seated apart. Once home, I asked our booking agent about a refund of the difference in fare between standard class and Eurostar Plus. An upgrade voucher for a future journey in one direction would also be reasonable. But the agent I booked through said: “In the