So I’m still diagnosing this vibration on the old mans 2010 auto.
Noticeable 1600-1900 rpm generally under load
No vibration at low speeds etc

I’ve noticed and assuming would should be installed that the rubber damper weight is missing from the n/s rear shock.

Would this cause a noticeable vibration?

Thanks Current - 2010 HSE Auto All Black
Gone but not forgotten:-
2009 Manual TD4e Manual HSE

LR wouldn't have fitted the mass damper to the rear struts unless they were required. These are normally fitted to reduce some form of vibration (harmonic oscillation) at certain times in the drive cycle. If there's one missing, then definitely replace it. Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, my daily driver.
1972 Hillman Avenger GT, the project.

Thank you...Never come across them before...will get one ordered. Current - 2010 HSE Auto All Black
Gone but not forgotten:-
2009 Manual TD4e Manual HSE

Nearly all modern vehicles of any quality have mass dampers installed in key locations. I expect the Fleel2 has half a dozen or more, in key areas of the vehicle, the drive shafts is common place to find them.

The Disco3/4 for instance has 2 enormous (about 25kg each) mass dampers, hanging from the rear chassis rails. Presumably these are there to reduce chassis vibrations. Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, my daily driver.
1972 Hillman Avenger GT, the project.