Helen and I have taken the Eurostar to from London to Paris several times. We love it. Train travel is so vastly superior to flying for those of us in wheelchairs that I cannot even begin to describe the difference. We have also taken the train from London to Amsterdam on several occasions, and although it is still much better than getting there by plane, the trip involves a change in Brussels that adds a lot of stress (and rolling; Brussels Midi is a very big station) to the trip.
Good news, everyone!