I always plan to need to remove the calliper carriers so buy in new bolts to be on the safe side as most of these calliper carrier bolts are either "stretch to yield" or end up only being good enough to use once as the "locking" serration on the underside of the flanged bolt head have been crushed during removal and so now not very effective, or rusting up of the bolt head means getting them back off the next time will be extremely problematic.
I could just about do it on my old Audi A4 with 155 rear discs but I doubt you can on larger rear discs.
To remove the carrier on the independent rear axle you'll need an M14 triple square tool.
These bolts are rather tight. 90Nm + 90 degs; And the manual says these bolts are single use - and renew after removing (torque to yield bolts)