Ex MOD defender 110 rattle

It's seems like a silly thread, you tell me and ex MOD landi circa 1986 that does not rattle. But this is a NEW rattle.
When going around roundabouts mainly, although sometimes on the flat there is a loud rattling noise coming from the gearbox ish area ?? Sounds very loud and has a sound akin to rattling bottle tops. The noise does not go away if I press the clutch or change into neutral. Not sure what it could be. Any ideas much appreciated but I know it is vague.

Noticed when she is cold it dosn't kick in for at-least 5 miles or so ( however this could be coincidence )

I would start by having a good look under the truck. The exhaust runs very close to the gearbox and there is a chance it is just this rattling or something close by.

If not it may be part of the hi/lo diff lock change mechanism that has come loose and is knocking against the gearbox.

Not sure if this helps but always worth trying all the easy to check things before looking deeper.

I had na ex army 110 for a couple of years and the heavy duty suspension causes a lot of vibration which I found was constantly making things loose. I have a civilian 110 now as I sumer salted the military one and I am planning on moving the suspension over as I miss being able to put 3 ton in the back (obviously not on the highway - lol)

Hope this helps

Cheers

Andy