i am having the same problem with water in the boot lid, although my rear screen and boot floor is dry.
will be going back to the dealer with a growing list of faults:
boot lid not perfectly alligned so "catches" when opening.
start stop only stops the engine for 1 second if anything electrical is turned on.
engine randomly turned off twice so far
very tappety when hot
1st gear very hard to engage when car is moving at any speed, even at crawl i have to wrench it in.
and now boot lid fills with water.
will be going back to the dealer with a growing list of faults:
boot lid not perfectly alligned so "catches" when opening.
start stop only stops the engine for 1 second if anything electrical is turned on.
engine randomly turned off twice so far
very tappety when hot
1st gear very hard to engage when car is moving at any speed, even at crawl i have to wrench it in.
and now boot lid fills with water.