Rather than choosing the <u>first</u> available Eurostar after you land, how about booking the <u>last</u> train of the day?

That way, you could get to the Eurostar terminal at your leisure, not worry about missing the train, and allow time for a little sightseeing on your way through London. You could go directly from Heathrow to Waterloo, park your gear at Left Luggage (&pound;6), and spend the rest of the day wandering around the city.

If you want to see lots of suburban London on the way in, buy an all-day bus pass for &pound;3.50, ride bus #412 to Victoria Coach Station and #211 to Waterloo. The trip will take about a half-hour longer than the Tube. The bus pass will also provide unlimited travel between the sights (see map): http://www.tfl.gov.uk/assets/downloads/cen_bus.pdf

&gt;&gt;how about booking the last train of the day?&lt;&lt;

Since they will be coming off a long overnight trans-Atlantic flight - Jetlag.

Might be a better idea to check into their hotel in London for a night and then spend one less night on the way back.

Yeah - but then you've got all the overhead of checking in and out and the requirement of getting up and out early in the morning to catch the train and the wasted half-day in Paris.

Once you board the evening train, you can collapse and catch a few winks on the way to Paris.