I haven't wheeled with Shawna a lot, but she went on a night run with the club a few weeks ago, she definitely can drive. If she's uncertain she asks for advice but then goes for it. I saw patience and both smooth acceleration and slowing down. It wasn't a jerky driving style. Actually, I think on this last run she out drove her truck. What I mean by this was that it wasn't her skill that was lacking it was the build of the rig.
Not being a Land Rover guy or really having any experience with them at all other than a few D90s which are a completely different beast. It seems she could have used a little more flex. The front of her rig and more particularly Dave's Disco 2 don't seem to flex as much as I was anticipating. I was expecting them to react similarly to an 80 series Land Cruiser. In chatting with them it seemed to make sense that adding a rear locker would make the most sense. They can't go with larger tires without doing serious axle modifications so adding a taller spring doesn't make sense. And really in this day and age who wants to daily drive with big tires when gas is over $4 a gallon and surely it will rise more in the next year.
They face the same problem I do. Our local trails have a lot of washes, a lot of dirt roads, but eventually they will have some rocks. It isn't continuous rock, but they are enough of an obstacle that some consideration to these formations should be given when building a rig for this area. So we aren't really rock crawlers, but we are to some extent for short intervals on a trip. It makes building a rig a challenge as building a rig for highway, gravel, two tracks and building a rig for the rocks are two different types of builds.
At this point I think adding a rear locker makes sense, because I don't think a flexy suspension with big tires is really an option.