I don't know a thing about Land Rover, but I do have a lot of experience about trans flushing. We perform over 400 trans flushes a month and service approx 140 cars per day. Two things I can tell you. First, if done correctly, it does nothing more than what your trans does on its own, we are putting new fluid in as the old fluid just pumps its way though the normal cycle, not allowing old fluid to re-enter, big deal, nothing get stirred up any more than when you remove the pan, you just get all new fluid. It works just the same as when you dis-connect you cooler lines and do a flush at home. Depending on the mileage it is nice to get a new filter, not for clogging but many start to come apart and the fibers can cause valve body issues. Second, I can not think of one customer recheck in ten years after flushing a trans, and believe me, they would be back looking to blame someone! Our only issue is the occasional leak from the connection point, normally old o-rings.
