Nothing any more.
I’d been noticing an odd knocking noise from the front of the X-Trail recently, so sent it round the corner to visit my local friendly mechanic. After initially assuming it’d be a five minute job to fix, he ended up chasing it round the car for a couple of hours, before eventually fixing it by tightening the top gearbox mount. On his way round he also found a broken earth lead and replaced that as well. It’s amazing how much smoother and quieter the car is now.
I think he did rule out the X-Trail as a replacement for his Terrano II though. The rear drive shafts aren’t beefy enough.