I thought I'd contribute back to the community as I have had this issue recently and solved it.

I've seen numerous articles online on this subject and I've spent hours taking off the interior headliner trim, taping up wires and connectors which I thought were causing the issue to no avail.

The issue I had definitely sounded like a rattle and identical to many others online. The issue is however caused by the sunroof liner on the outside of the car. (My car has a fixed panoramic sunroof that does not open). I know it sounds odd and you are probably thinking it's not causing the rattle however I can assure you that it solved my issue.

All you need to do is buy silicone grease (link below to the one I used) and apply it to both sides of the rubber lining at the front and rear of the sunroof (on the outside of the vehicle). The gaps are really small and tight so I used an old credit card to slide between both sides as I applied the grease. Once done simply wipe any excess away and the issue will go.

https://www.amazon.co.uk/gp/product/B00S1C...&psc=1

The issue is essentially caused by the rubber creaking (although it sounds like a rattle) and occurs when the car's chassis bends slightly as you drive over bumps, etc. This same issue occurs on almost all cars with sunroofs and is the result of the rubber drying out slightly. For reference my car is literally brand new with less than 5K miles on and is a 2020 model. The rubber looks brand new so don't think it only occurs in aged vehicles.

I hope this helps anyone and saves you time troubleshooting and taking trim off etc..

thanks!  --
2010 Defender Puma 90 + BAS remap + Alive IC + Slickshift + Ashcroft ATB rear
2015 Range Rover Sport Supercharged V8 HSE Dynamic



Defender Puma Workshop Manual: https://bit.ly/2zZ1en9
Discovery 4 Workshop Manual: https://bit.ly/2zXrtKO
Range Rover/Sport L320/L322/L494 Workshop Manual: https://bit.ly/2zc58JQ