Freelander 2 (LR2) New prop shaft noise - alignment?

Hi all, I've just installed a new (OEM) prop shaft onto my vehicle. I've been running in 2WD for a couple of weeks but have finally gotten round to putting the new one in place.
But now there's a noise, most obvious if just going downhill with no accelerator but also when slowing down as per. My question is: is there any alignment that needs doing, or do (should) the shaft self-align simply by virtue of the various mounting points?
Thanks

The mounts should be at 90° to the shaft, and if it has 2 mounts (a 3 piece shaft), then the centre shaft should be on the center line of the vehicle.

Are you sure the noise is from the shaft? It's very common for the rear diff and PTU to suffer wear, resulting in noise.

Hi Nodge, the only answer to that is twofold (though one might be me talking through my rear end) in that when the shaft wasn't installed there were no noises.
I had previously, and briefly, installed an aftermarket one that was simply awful whilst driving. The new one (if its the culprit) isn't as noisy but still..