Hi everyone. I have found the origin of the troublesome leakage. Firstly the glued back windows had a slight leak but now sorted after I went to a window repair shop. They helped me on the spot without charging. Secondly I found leakage from the trunk. It is wherefrom the electric cables goes from the trunk into the car the leakage starts. Those rubber seals were not tight enough. I aligned them better and used my silicongun aswell. I emptied the trunk Of all interior and found a puddle of water. The car is now in a dry garage drying. Hopefully the silicon will make the trick.