I'm not sure how wind deflectors would be fitted on a frameless window with a convertible roof.

When the cars left the factory they were wind and waterproof. The window is obviously out of adjustment and simply needs readjusting - although this is not a simple job. A time consuming and fiddly job to get right, but needs to be done.

Agree but before I tried to adjust the window I’d check if it’s not as simple as the door has dropped - usually obvious if it has because of the swage lines in the body work.