Rene,
If its just suddenly started leaking first check your seal in the hood rail and make sure it hasn't folded in on its self especially at the outer edges as this allows water to track along the length. Next, make sure your hood rail is properly seated fully down on the screen top. then check your screen/hood fixing clips, is there enough tension on them to hold the hood rail snugly against the screen top. Often there is not and if the hood is a little tight the vibration allows the hood rail to lift enough to allow water to enter. If you have to adjust the hood clip to screen toggle clip do not over tighten it so that it takes force to clip it down as you can break the weld in the hood frame and it will need re welding.... a real faf of a job! Rather it just needs to be adjusted to hold the top rail in the correct position with just a little tension only!
I use a gel silicone lubricant sparingly wiped into the inside of the rubber channel and find this helps seat the hood to frame easily and helps prevent water ingress. Good luck with a fix. If you need a new seal try the BHM site parts finder or Melvyn Rutter.
