The first place to check is your local canam dealer, the online canam parts does not not show the heater option but the shop manual does show the louvres separately so they should be available.
I found the 2019 XT cab enclosure in the 2nd lowest item on the online parts list Defender series, 020 , 03 09. The part number is 520001681, its called a round grid and retails for about $20cdn. Be sure to check with your parts person to confirm this is what you want before you place your order? FYI
It looks like you have two tabs that have to pop out, try and pry gently with a small flat blade screw driverfrom the front of the panel first? It is also possible that they rotate to lock into or release from the locked position?
Easy Peasy, used a painters tool (I thinks it’s a 5 way painters tool) anywayI was able to slip behind the rotating collar and kept it pry’d open with a small screw driver and rotated the painters under the flange and it basically popped out. That allowed access to the fixed collar where I sprung open the retention tabs with the small screw driver. The new one is “clocked” with a male alignment into the female slot at the 6:00 o’clock position. I didn’t think of it till after I installed the new one. The louvre is inside the unit.
I am new to this forum, or any forum for that matter, but I did research replacing the heater vents as they were all broken on my 2018 Defender when I bought it. I just figured out what I feel is an awesome and cheap fix. I don't want to spend time posting details and pics unless people need it given this thread seems several years old. Please let me know if anybody still wants this info and I will add my info to share with all. Thx