Store Management (Service Manager...General Manager ... Regional General Manager, if Dealer Group...Owner - in that order). Then contact JLR-USA Customer Service.

Don't "lose your $41T". Talk logically and politely how you care about their customer service as well as their social media image. "Nothing looks better on a Review than when a Dealer solves a challenging problem"....

 

This is clearly a warranty matter. I know another member here and Kirkland local who had the same issue, resolved under warranty AFAIK.

I think it sounds like the same issue. I've seen it on other Defender groups too. Seems to be a well known warranty item.

The good folks at JLR Bellevue know jack about the Defender. Completely clueless on spec, trim, warranty issues etc.

I'd go straight to the GM. Failing that LR USA which are likely going to be as useful as a chocolate teapot.
This is 100% a common issue. Common enough I've seen it posted about many times. The fixed portion of the rear window flapping loose. 100% Unrelated to the lunch box.

@ADVAW8S What did you get done for the flappy window trim issue?

 

You will find that there are dealerships that seemingly try to not submit warranty claims even if it seems obvious it is. I worked with technicians who would just go out of their way to be the "warranty police", for things like this. Just wasting hours of time and not getting payed to fix problems. Then complain at the end of the pay period that they have a low paycheck. Amazing! I understand that they have to follow the rules, and they should. They just sometimes make up the rules as they go, like telling people if the modify their vehicle or go off road, will void their whole warranty! Just nonsense. Dealerships are not owned or run by JLR. JLR is just their best customer. They pay the same labor rate as a customer does, however, they determine the labor time that the job pays. They also have the warranty contract you signed with them that has the limitations. On customer pay, the warranty time is usually bumped up by some type of multiplier. They dealer typically has a warranty clerk that the technician can check with to clarify if it is covered by warranty. We always used the masking tape method to determine the cause of wind noise. You could request to ride with the tech to confirm how they came to the conclusion that the loose trim (which i would assume should be warranty anyways since it is loose, being the cause of the wind noise or not...) Is not the wind noise and why the removal of the lunchbox is. Or better yet, just ask to ride with the shop foreman.
To be honest tho, i had a belt pulley noise from my engine. I ended up ordering the part and installing myself. My defender is still under warranty. Our local dealer is not great. So i prefer to not deal with the horrible appointment that is 2 months out, then deal with the "you use this off road, so the mud caused it....) nonsense. Sometimes it is not worth the "free" repair, since you still just pay in headaches. I would just buy the 200 dollar part and fix it yourself. Life is just too short. Just my 2c

 

Just noticed mine loose on the left rear door (drivers) on my 2020 110 -- with 2 months of warranty left. We had our first chilly morning this week here in Oregon, wonder if the temperature change worked it loose.

Scheduled into the dealer to take care of it.

What an odd thing. You can see straight into the vehicle if you prise it out.