2016 ND, 25k miles.
My MOT tester said he had to free off a stuck front NS calliper, after driving home I noticed that wheel was unusually hot compared to the others.
The pads were almost down to the metal, after replacing the front pads I noticed the disc was catching at one position on the NS, so I fitted new front discs.
After a 5-mile easy test drive, 3 discs are 40…50 degrees c, the front NS was 100c!, it must be an overheated bearing right? so I have ordered a new hub (what happened to being able to replace just the bearing!)
Rant over, does anyone know the torque spec for the hub bolts?
Are you sure that the caliper was freed off successfully? I’d suspect that before a bearing issue.
I hadn’t considered that, when I changed the pads on that side I had no issues compressing the piston to get the new pads in, I had ‘assumed’ the seize-up was due to thin discs and thin pads overextending the piston.
What testing can I do to check the calliper before I fit the hub?
If you’ve checked it yourself and your happy that it’s free then maybe it is the hub then. I’d get it jacked up in its failed (tight) state then remove the caliper and see if the wheel frees off.
Just checked both wheels and the OS spins easier than the NS, but that could still be a failed bearing right?, going to have to get the calliper off again to see if it lets the hub spin easier.
Do the do rebuild kits for these or would I be ordering a new calliper?
After applying and releasing brakes the OS wheel spins easy, but not as easy as the NS.
I removed the calliper and pads, the hub spun a little easier, but not a huge amount.
Reassembled and drove 4 miles at 60 stopping using engine braking as much as possible.
The other 3 discs were 15/20c, the front OS was 98c.
So I am 100% sure it’s either the calliper or the bearing, but no idea how to determine which!
Found a used caliper on the bay in what appears to be very decent condition (others look like blocks of rust!) for not much money so I’ll give that a whirl before I unbox the expensive hub!
Cheers for the suggestion, could save me a ton 
Cheers Robbie, I owe you a pint, swapped out the caliper and it’s fine now.
Looking forward to the National Rally then. Happy to have helped.