The problem for the Land Rovers is not that they can't handle the weight of all the infantry gear, it's that they can't handle the weight of their modernisation package.

They're soft-skinned light fast patrol vehicles, originally specced for use behind friendly lines and in Northern Ireland - up-armouring them for a modern battlefield, improving their radio gear and extending their range adds a lot of mass. It got to the point where the weight of the extra gear risked breaking an axle if they drove off-road at one point, iirc.

Thankfully the REME engineers are actually listened to when they say "this is provably unsafe, look", so they're getting new vehicles at long last.