ORIGINAL: Glyn
I did watch this process and saw that only a few bleeds per calliper was done before they moved onto the next calliper, master cylinder was topped up after each calliper was done, The plastic container that held the old fluid didn't appear to have a great deal of fluid in it after the entire bleed and although I didn't get close up or have the opportunity to really see just how much fluid had been changed I do know that 4 top ups of the master cylinder wouldn't have purged the entire system so I guess I have no proof, H&S prevents non employees being in the workshop.
Im not saying that a partial change of fluid is a serious issue because if that amount of fluid was changed every two years then at least I am confident the moisture absorption in the old fluid would be microscopic (as the entire fluid would have been changed completely after 4 years and two fluid changes), Im just saying that £150 for a ten minute £10 worth of new fluid is highway robbery, very poor value and is just opportunistic profit generation based on putting the fear of brake failure into customers.
It is after all just a recommendation, but delivered in such a way as to have you believe you are taking a chance and risking your life by not heeding their recommendation.