Whats that noise?

[noogie]

Hi all

Just wondering whether someone can shed some light on a noise image getting from what appears to be the front of my defender.

It's a loud cracking noise. High pitched.
I've just had some work done. Both cvs and axles changed.
Front diff has an ashcroft locker in it.

Im hoping it might be a worn bush as it doesn't happen all the time.
Sometimes you'll hear it just driving along a flat dirt road.
Once going down with a little articulation.

I've only ever heard it in low range.
When you rotate the front prop shaft there is movement but that's always been there.
I had a major service done and there was no mention of bits of metal draining out of front diff.

Gonna put my car on stands today and check for anything that might be loose.

Any thoughts ?