I've taken the Eurostar in to St. Pancras from Brussels but never out.
Is there a "good" time in so far as being less crowded to depart from St. Pancras? I'll be in London in February and will be taking the Eurostar to Paris. I'm debating between leaving between 7 and 8 a.m. or waiting until 9:30 to 10:30 a.m. I don't have to be in Paris at a specific time but have heard it can get quite congested at the Eurostar check-in. Is that because you can check in for your train at any point at St. Pancras? (In Brussels, we couldn't check in until 45 minute prior and so the lines weren't terrible.)
Any info, advice and opinion is much appreciated!