I agree with other friends - I'm sure it would be much more hassle to go to
Paris via Eurostar. I actually like the train and you are only under the
channel for 25 minutes or so. 3 hours Waterloo to Gare du Nord is excellent
and it is great to be in the heart of Paris so quickly.
But to get to Eurostar terminal from either Gatwick or Heathrow would
involve at least one change of train (and with all your luggage too!) plus
probably having to connect from Waterloo East to Waterloo International.
Organise an onward flight to Paris (they are frequent from both London
airports)- your luggage will be transferred for you and you will arrive in
Paris far less hassled!
Sally, Somerset, England