ok guys you all may want to check this on your mk1s, if you follow each chassis leg in engine bay to where it meets the bulk head you may find a hole which at the factory was covered with a tape, the hole is about 25mm across, this should be covered or you will find alot of water in cabin, a 24mm flat grommet from halfords with abit of silicone on it will cure the leak.
this hole is on each side
