Another front suspension question from a rookie
I had noticed before taking the struts apart that the dust covers had come loose on both sides and figured it would be an easy fix when re-assembling. I see how the upper end will sit inside the bell of the shock mount, but I can't figure out what is supposed to hold the lower end of the cover in place? It fits snug over the spring retainer, but that would leave no room for the plastic spring washers. What am I missing here?
Thanks!

You're not missing anything. They don't attach at both ends. When the shock is compressed with the weight of the vehicle the boot covers the exposed part of the shock. It's just there to keep serious gunk off of the shaft. It's not intended to be a complete seal like the boots on the steering rack, for example.

Wow, I would never have guessed that to be the case.
Both of mine had plenty of gunk inside them, so it really seems like a design flaw.
Thanks!

Make sure to lock it in place in the small bell with the bump stop (spring assister) and it's good to go.
Any attempt to seal both ends that is not 100% successful would result in a hidden chamber of rot, particularly in regions of severe weather and road conditions.

Jaguar ensured your shocks don't get too dirty by making shock mount bushings that disintegrate on a regular basis, ensuring you have to pull your shocks apart and clean them every few years.