As above, defender coils are about 30mm wider in diameter than standard, but they are cheap. On an A series you have to add Landrover spring seats, you can just make out the LR seats bolted over the originals
& you can make them fit in the top seats with the right isolation rubbers. Sorry, the picture attached isn't the best, & one day, I'll add a full report to my build thread.
Also, If you go with green oval springs, watch the poundage. I run with 340lb springs, and while they're good with my usual boot load (about 400kg day in, day out) when its empty it's way too hard for comfort