For what is worth, pretty much any old Land Rover is not going to fare well in freeway speeds rollovers. Off road most should be OK, but a Defender is not much of an improvement over the old series and those were removable and not that sturdy.
a 110 is not for a beginner there are much better more modern 4x4 that will allow your friend to get into this much safer, a 110 is for the few of us that are crazy enough to own an old Land Rover or two and wheel them, knowing very well what we have.
My 2 cents.