Land Rovers - often used for putting boats in salt water - hence the rotten rear of chassis.
That said my mate, Sean's just spent a couple of weeks replacing the rear section of his K-plate TDI, so it may just be that 'they all do that, sir'.
He had to do the front outriggers as well. Have you poked about with yours yet?
That's the thing about Land Rover's - they're so badly engineered, there's always something f*cked.