The land rover seat box has not changed much since the first series land rover right through to the defenders. It is a pretty simple construction, a bunch of aluminium panels riveted together with three lids under each of the seats for access. On the passenger side there is a steel tool box, which has a cutout for a second battery. Overall the seat box box was not in bad shape, the sides were damaged where it bolts to the chassis, there was quite a bit of galvanic corrosion where the steel seat rails bolt onto the top and the bottom of the battery box had some rust holes.
I decided that it was easier to buy new side panels than repair so I ordered a new set from Emberton Imperial. They are really nice reproductions and are worth replacing as they are one of the the first things you see when you open the door.
The tool box needed some work it had multiple holes in the bottom where moisture pools, it is a common issue. You can buy replacements but I decided to cut our the rust and have a go at repairing it. I drilled out the spot welds and removed the bottom. I made up a new section for the bottom and plug welded it on and fixed a couple of other rust spots. It came up pretty well. After seam sealing it, I put some undercoat on it ready to reattach to the seat box.
The glavanic corrosion caused by the contact between the steel seat rails and the aluminium seat box made it look a bit ugly, so after sanding to remove all of the scabby looking oxidation I put a thin layer of filler on and sanded it back again ready for paint. When I reinstall the seat rails down the track I think I will put in a thin strip of rubber to try to stop it occurring again.