The carbon fiber exhaust there isn't a heat shield. The canister is made out of carbon fiber. It will run cooler than any metal canister, but it isn't a heat shield. The OEM heat shield for the exhaust is just above the rear brake MC on the right side. That's to protect your legs though.
There's no sort of heat shielding that can be applied to that area. Hopefully you've told your GF that she shouldn't wear flip-flops on a bike and that over-the-ankle riding boots will be the best protection from the heat.
That's the BEST slip-on for that bike BTW!