I used to carry dozens of tools and a bunch of parts. Only ever used duct tape, cardboard and a trash bag, loaned a spare to a RRC with none, One of those tire sealers to another, and jump cables to charge the battery of a third with a dead alternator.
A friend of mine runs a land rover / range rover specialty repair shop. Based on his experience, they are capable of stopping anywhere, anytime, at any cost.
I don't know about the brakes, only their unreliability.