From the press pics it looks like one of the clues is read behind a giant poppy, the reverse of where teams checked in at the pit stop last leg.
Surprisingly the clue being opened is a Roadblock; for the sake of not having to have too many extra people involved I guess they're forced to pick, then drive there - a 200km drive isn't completely out of the realm of possibility (especially if they start early in the day which I imagine they would).