It's been a while since I travelled on Eurostar. What do they do with the luggage - is it checked in like it is on an aircraft and stowed in a separate compartment, or is it 'carry on' - i.e. do you carry your own luggage onto the train and take it into your carraige?
I ask because if the latter I shall try and concertina it into one suitcase (proving really taxing) but if the former I will throw caution to the wind and use 2 suitcases.