Dropped Rear Suspension

[jharrawa]

I have a 2004 Berlingo van which following a clunk today is now sitting very low.

I've had a look underneath - both torsion arms are intact but it looks like there is a gap around one as it enters the NS trailing arm. Is it possible that it's skipped some splines?

A quick bit of research suggests to bite the bullet and replace the whole rear axle, but some hints and tips on where to get one and how to do it would be appreciated.

Apologies for the post, I'm sure I can search the forums, but I needed one post to download a link from another thread!