So, I am going to do the rear pads and discs. I have checked the disc screw can be removed (I had to drill the one when I did the job at the front.

After watching the normal YouTube videos and reading the manual.

Do people use new bolts for the carrier to upright? The manual says they need to be replaced. Lots of videos show them being reused.

I will use new ones. I am just wondering what others do.

Like the wear sensor. I will try to re-use it, it hasn't triggered the warning, but I was told to replace it by the dealer. Again in the videos, it is a mix they replacing or not.

The last are the 2 bolts that hold the piston to the carrier. The manual doesn't say to replace them, but I am thinking that for the cost I will probably replace them. SDV8 AB MY 2020
MINI Cooper S Cabrio
Kit: Jaguar XK140 (in progress - the website is link to build)

I tend to renew but I have reused these bolts before. If they are in good condition and you use loctite on the threads they should be fine.

It’s how many times they have been used/stretched that is the issue. It is good practice to put a punch mark on the bolt head each time they are used so you n
Know how many stretches they have been through - 4 is usually the max.

The bolts that attach the caliper to the carrier are less of an issue if reused as these are a much lower torque setting.

Bolts are fairly inexpensive so if you do have new ones I would replace them .

Spot on advice there from Alex, as per the WM, carrier bolts are “stretched” and should be replaced every time, the 35Nm ones holding the calipers to the carrier can be reused with a little Loctite.
Always remember Loctite damages rubber parts, so use sparingly.  “If it ain’t broke, don’t fix it” -where’s the fun in that?