Sorry,I dont know the mk1 . But I would have thought in the area of your photo any rainwater would already be in 'free fall' through the engine compartment to the road. You may do better searching higher, in the area covered by the plastic panels with grills in the vicinity where the wipers park. Relatively small drain holes tend to get blocked by dead leaves, dead insects, dirt ,crud etc in the area under this grill. Trapped water can form pools and tries to find its own way out, maybe into the car interior.
Look through the grill for signs of 'mud' and damp, or even pooling water. The blocked drain hole is likely to be hidden under the mud and you might be able to clear the blockage with some stiff poked through the grill . If all else fails it may seem counter productive but try flooding the screen with water to see if a pool of water forms somewhere which highlights where it should be draining away. . If I am wrong and water is not draining from the area of your photo you could try the same water pooling detection technique there too.
Hope this helps. Good luck, leaks can be pigs to trace, water can tickle quite a distance from its source, along seams etc. But getting the car dry then making it wet again can sometimes help you trace its progress back to a source,.
Also poke some wire through the drain hole in the bottom of the passenger door. If water entering via the window cannot escape it can pool inside the door bottom then trickle over into the footwell.
