I am currently repairing my bulkhead on my 1989 90 and have noticed that there are two small factory made holes either end of the windscreen frame ledge. Were these intended for drainage (under the seal) and is there a concencus whether they should remain? I ask because it is in exactly these two positions that I have suffered rot. Perhaps they were an attempt by Landrover to mitigate a known issue with corrosion with the top of the bulkhead corners?

Are these the holes on top of the ledge? If so they are for location pins on the screen frame. A pic may help.

Yes, the holes are in the top bulkhead ledge that the screen frame sits on, about 30mm from the end. There are no locating pegs on my frame, just the ones on the bulkhead ledge.

Mine has rotted where these holes are located, so don't have a picture to share I'm afraid.