Water ingress is a total nightmare. Wife's Juke leaks somewhere and after extensive checks we still can't work out where. You may be lucky that you have found the issue - now it's a matter of sorting it out. I feel your pain.
It's not coming into the car, which is a blessing. I kind of always knew it was slow draining as you'd see a wet patch and drips under that door even on dry days. The Northern weather just tipped it over the edge I think.
Briefly, when I was sat in the rainy car park. Will take a deeper look now.