I did the drain and new filter on my X350 a couple of years and my other car L405 Range Rover is now due for a service but I'm undecided which way to go. Do you think the full flush is best and will they change the filter as part of the service? There are a lot of different opinions ie: Leave it alone, drain and refill a couple of times or full flush. Must admit the latter seems to be the way to go as drain and refill x several seems very wasteful. also any views on which fluid to use? The Lifeguard stuff seems ridiculously expensive when other brands have exactly the same spec for much cheaper price.....but will it mix ok? questions, questions.