I finally got around to checking mine - not glued in!
But - I did find, while looking, that the dreaded crack across the top had appeared.
I think this is just a design flaw due to the seat compressing while the driver slides out of the seat to exit the car and the driver's weight is then applied to the plastic surround.
My car is under Selekt warranty but I doubt somehow this will be covered...
Regarding epoxy glue - I used Araldite on my old Saab 9-5 Aero Estate to deal with a similar problem on the passenger electric seat surround and it worked OK for a couple of years but eventually failed again - the glue just seemed to "soften" a bit and released from one of the surfaces.
I suppose what I am saying is that you need to make sure there is a reasonable "key" scratched into the surfaces to be joined to get the glue to hold.
An alternative might be MekPak (Methyl Ethyl Ketone) to actually "weld" the plastics together - but it's dodgy stuff (if you can still get it...)
Edit - yes you can -
https://slatersplastikard.com/plastikard/mekpak.php
I used to use it for model making back in the day
Cheers
Dave