[modern] XK8 Defroster Vent Removal?

I have a 97 XK8 Convertible. My defroster vents in the upper dash
rattle against the base of the windshield, and I’d like to remove them
so I can determine if I can find a better solution to the rattle than
just sticking rubber blocks in there (like I have now). I’m considering
just filing down the leading 1/8th of an inch to make them a little
shallower. Does anyone know how to remove these vents? I’ve looked at
the JTIS CD but without any luck.

Thanks in advance,