I mounted an Icom 208H in my LR3 (Disco3). It was straightforward, but I was unable to use the wiring loom grommet in the firewall due to access difficulties under the brake master cylinder assembly (in the spare battery compartment on the left-hand-drive Driver's side). So instead I went through the steering linkage grommet, taking care that the wire would not foul with the steering rod, and sealing everything back up with dabs of black silicone sealant. I ran positive and negative (earth grounds) straight to the battery, using 18 gauge wire if I recall correctly.
I mounted the radio itself under the second row seat, along with a speaker, all on a removable wood platform. All in all, it seemed to work pretty well for me. I was able to remove the assembly completely without leaving any marks or visible holes.
Here are a few photos:
Cheers,
Nathan
EDIT: I found a few more photos on my web server: