I was lucky enough to pickup a complete set off of eBay.
They were not in great shape, but they went into the car anyway as the existing suspension was absolutely shot.
They have since gone back to GAZ for a rebuild, and come back completely rebuilt and ready to go again. Just waiting to put them back into the car. The only thing GAZ can't supply is the lower rear bush and rear gaiter. I've had to buy new rear Boge dampers, and then cannibalize them for the parts.
GAZ themselves were surprised to see the rears come back in. Apparently they only made around a dozen complete sets - due to the unavailability of the lower rear bushes. Jaguar don't manufacture them anymore.
So the rears are hard to find I'm afraid. That being said, you could always query GAZ themselves and ask if they make you a set. They were very accommodating when I spoke to them regarding mine.
As for the springs. Mine is the V12, so I have gone with Berkshire Jag Components own set of front and rears. As there isn't much alternative for the V12!
I've then coupled those with the sportspack spacers from Jaguar to give it a lower stance.
It'll hopefully all work together well, eventually!
1993 4.0 Sovereign, Flamenco Red.
1994 6.0 Daimler Double Six, Silver Frost.
2012 Mercedes E350, Obsidian Black.