A bulkhead repair on a Land Rover need not fill you with dread. It's simply a matter of cutting out the rot and replacing this with sound metal. Apart from the footwells (which I had already replaced), the other place where rot usually occurs on a Land Rover bulkhead is at the top corners under the windscreen. This was certainly true in my case.
Repair panels are available to purchase, but as I had some scrap sheet steel available I decided to make my own. I first made a cardboard template to cover the area of all the rot, and bent it into shape:
Using double-sided tape, I then affixed this template to the sheet metal and sprayed it black so that an outline would be left, making it easier to cut out the repair piece. The sheet metal here is actually the remains of an old Land Rover tailgate which I dismantled. I found that it is actually galvanized which should help prevent any further corrosion. (Of course before welding it one has to remove some of the galvanizing along the weld lines in order to ensure a good penetrating weld).
Here is the shaped repair piece:
The repair piece was then put into place on the bulkhead. I marked its position, and then cut away the marked piece, leaving a hole into which the repair piece should fit snugly.
I had to file away a few of the edges, but finally obtained a fairly good fit:
I then used a sander to remove the galvanizing from the edges, so that a good weld would be obtained. Here's the finished item, with the bracket for the vent cover in place:
I did the same repair on the passenger side. Once everything was all welded in place, I removed all the old paint with a wire brush on an angle grinder, taking it back to bare metal as far as possible. I then used body filler to fill in all the joints, then painted everything with Unidox primer (a 90% zinc coating). The bulkhead was then put to one side ready for the top coats once I have finished renovating the chassis.