I have also had water leaks through the join between the scuttle and the bulkhead, easily fixed with a smear of black silicone sealant.
A few years ago I did some modifications to the fuse wiring, which on a 1986 car are all on top of the bulkhead on the flat surface above the driver's legs. During the course of the mods, I removed one fitting which left a 5 mm hole in the bulkhead. Not having any grommets that small, I just left it.
I forgot about it until one day when I was driving in particularly heavy rain and I got the drip-drip onto my leg. I had a long way to go, so I pulled into a lay-by, got a bit of stick out of a bush, whittled it to a short tapered bung and jammed it into the hole. It worked a treat, and has been there ever since...
