Can anyone tell me why i have water coming in the top corner of my 90 Defender door, its only coming in the drivers side after its been raining, could it be leaking in via the sun roof and coming through the top of the door ?. Any help please

There are a number on ingress points. It could be the sunroof/seal, it could be the the gutter, do you have a seam on the roof ?
The door seal itself ?

A good clean and then an application of Captain Tolleys Creeping Crack Cure (i'm a big fan) may help.