re: Best one way option from London to Paris ?

We took the Eurotrain from Paris to London then back to Paris after 2 days in London. We had lunch and dinner on train and it was very good. Make sure you just choose off times when you travel that way you don't overspend with the people traveling for Business which are usually between 7 am and 9am and in the afternoon between 2 pm and 5 pm. We saved hundreds by just picking off times. BTW this was precovid so I don't know how they do things now.