As above this new to me has a clunk on the rear, not all the time and does sound like something in the boot moving.
Car has full dealers history.
Does the E diff make a noise?
Only does it moving off and not all the time?

fuel slopping around in the tank ?

No it’s something moving.
Does the E diff make any noise?

Possibly the transfer box needing a double flush. Lots of posts on that here. Clonking when taking off, like something in the boot. Once moving it vanishes. I had that took it into Mikey couple of weeks back, double flush, recalibrate something, noise gone. Early days but seems positive. Used to drive me nuts

Mine does have a clunk too . Had in to MD who advised all 4 ARC bushes were shot and were the first port of call. Replaced all 4, made zero difference. Weird thing is , my first 405 (2013) did something very similar, 3 clunks when pulling of from a standstill, and sometimes on a rolling take off from a roundabout. It's way more pronounced with the newer one though, and just heard it when reversing in a parking space which is a 1st.

I know as soon as I book it in , it's open wallet time, I just don't know where to start. It has full S/H so all fluids have been changed to spec, however transfer case might be the logical starting point . 2019 SV AB Dynamic Scafel Grey

Hi
See my post
https://www.fullfatrr.com/forum/topic73369.html
Does it sound similar? I have not found the answer! 2018 4.4 TDV8

Hmm thanks for that.
Transfer box and both diffs just done at last service and I did have the issue associated with that on my last 4.4 and it fixed it, this is different, it’s like the rear is moving.
I need to find a garage with the ramp that has the shaker plates and have a look on the rear

RR YORKS - sent you a pm .  2019 SV AB Dynamic Scafel Grey