I'm confusing myself!!!!!
So if we book 90 days before, we still put in DLP (not Lille) and the Eurostar site will come up with options for the indirect service, at (hopefully) cheaper prices?
yes, thats right
If the 2 tickets will be included in the price, any idea how much it's likely to be on the first day to book? Don't want to wait and then find it's only a few pounds cheaper than now and had all that wait and worry for little reward if that makes sense? Can you tell we've only ever booked direct before?!
my indirect fare between Ebbsfleet and DLP, booked through Eurostar as soon as the fares came out at 90 days, was £39.75 per adult, and £37 per child.

