I have a Swift Accord 590 model 2007. It had a leak at the back window. I had to totally remove the whole rear panel on the inside as well as the furniture, replace the rotten wood and rebuild it.
I found nails and screws in the rear plastic panel that had split the plastic from it’s original manufacturing and assumed this was the source of the leak.
This was on the screws attaching the rear window and also Under the awning rail. I removed and resealed the awning rail.
All of this took me a year and lots of Sikaflex. When it rained there was no leaking into the c