Hi, what is your defender?
Mines a TD5 90, Iv done a few bits on mine you might consider upgrades? or a waste of money.
I made some seat risers from 1" box to move the seats back over the bulk head to get a better driving position,
You can buy the risers if you dont fancy making some.
But then my knees touched the big old bus steering wheel so i swapped it for a smaller one, be aware a lot of aftermarket steering wheels dont come with the boss to mount them on your steering shaft you have to buy them seperate.
I put a 15" on mine and i now like it.
Iv put a bigger steering damper on mine because the original was tired, easy job.
Iv swapped a lot of body bolts for stainless ones, to stop the horrid rust marks all over the body work, I coated them in grease to hopefully discourage them from causing ally rot, maybe!
I swapped the centre exhaust for a straight through pipe because mine was all dented in and blowing.
I bought a set of disco freestyle alloys, which look better than the rusty steels that came on it.
Next for me is replacing the transfer box with one from a disco to make it less noisy on the motorway, it does my head in

Everythings been done on my Mates drive.
If you know the difference between a ring spanner and a hammer most things seem do-able