On the first 2 visits (1 day each) they couldn't replicate the leak, so were working blind. I work in IT and understand the problems associated with trying to fix intermitent faults....and if you can't replicate the fault, then its nigh on impossible. They adjusted the window on the first visit, but that made no difference. I can't even remember what they did on the 2nd. (edit: on the 2nd visit they tried to replicate all the asdjustments from the drivers door onto the passenger door).
The pattern seems to be when its in the rain for several hours - it mainly happens overnight, but has happened sometimes when sat at work all day. It isn't dependant on heavy rain - just constant rain, cos one day it was just that fine misty stuff all day and it leaked, but the the other night it was quite heavy and nothing....although I didn't check it till 12 that day, so it could've evaporated.
On the 3rd visit (3 days) they said they replicated the leak by leaving a hose on it for over 4 hours. Not a pressure hose, just a garden hose with constant water. They said part of the tape holding a seal to the roof was missing, so they were replacing that. They let that dry overnight and re-tested the following day...all dry.
Except it wasnt!
So the last visit was for over a week. I think they just guessed at adjusting the seals. They said they'd had it on test for 4 days and no leak, then the day of collection it leaked!
Needless to say, not fixed.
I dont doubt that they've tried hard, but they now admit they have nothing else to try, apart from changing the seals, so they are talking to BMW.
Regarding all convertables leaking - having no prior experience of convertables, I cant comment, but looking at it from my point of view, I dont think the amount of leak as shown in my video is acceptable. Ok, one or two drops now and then, but this is too much. Also, my logic questions why the driver side is bone dry, whereas the passenger side, although not everytime, is more often than not wet. I dont think I'm being too picky - if this was to be expected then I'm sure others would've had similar experiences.