With the brakes bled and the caliper handbrake adjusters working, I could finally connect the handbrake cable to the rear calipers.
To hook the cable onto the calipers I had to loosen the cable with the adjuster almost to the point where the outside of the cable touches the handbrake pulley.
The adjuster is on the right-hand side of the differential. The cable loops around the drive shaft, then doubles back towards the caliper. Once connected to both calipers, I adjusted cable to the three clicks advised for IVA, but I only did that to torque the prop-shaft bolts. Once that was done, I adjusted the cable again so the handbrake lever would reach its maximum up position. This is needed to fit the transmission tunnel cover later, so for now there is no point securing the handbrake cable down.