I want to book Eurostar tickets from London to Marne-la-valle-Ches station (Disneyland Paris) on a Saturday in June, but I'm unable to do so on the Eurostar website. The calendar only goes until May. I thought I could book these 6 months in advance. I'm really hoping the direct 10:15 train runs everyday and that the calendar for June is just not open yet. Any help?
Drilling down into the details, this train only runs Sunday, Monday, Wednesday, Friday in the month of June. That's what DB is showing. Looks like you will need to change trains at Lille Europe, or adjust your date.
Sam's details match this December news brief from the editors of the European Rail Timetable: "The Eurostar service to Paris Disneyland is running on four days a week instead of the previous five and will not run between January 5 and February 7."