Now the sun's out, I can crack on...
Rear beam and diff painted with epoxy paint, and fitted.
I hope to remember to fill the diff with oil

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Break-away torque was more than 60Nm, but less than 70Nm, so the clutches are good.
The backlash was 0.0025", so that's good.
New bushes. I used poly, as they are very easy to fit. I burned the old ones out. I reused three of the "bolts of death", but one had become an 8mm hex instead of a 6mm hex, so that's now a hex-headed screw and washer. I had to use my butchery skills to carefully remove the remains of one of the exhaust hanger bolts on the beam, but success.
I've replaced the handbrake cables.
Next is the rear arms and driveshafts. I've cleaned one, and hope to clean the other tomorrow. Then paint and fit them.