I changed mine at 52'000 better to be safe than sorry, there is an idler pulley that i would change too along with the waterpump, 85'000 on a waterpump is allot and to change the waterpump its a hell of a struggle without having to remove the cam belt all over again as its tucked behind.
Good price on the fitting, i hope the garage realises that the cam cover has to come off and the pulleys have to be loosened due the VVT, if they dont do it you will get a EML