those aren’t the slider guide pins, those are the t50s that hold the caliper together. pop the rubber cover and there’s your 7mm/9mm allen head slider. that’s how the caliper comes off the bracket, you’re not supposed to touch the T50s and they’re probably only sold with the caliper.

 

I will have to check the car tomorrow. Isn't this a picture of the rear caliper though? And still, Jaguar still lists this was 12mm when I keep getting 9mm bolts

https://parts.jaguarpalmbeach.com/p/.../C2C27297.html

 

12mm is the total pin diameter, M9 thread

there’s also a 16mm M10 guide pin on some cars. that’s what i sent you. under the rubber cover are your guide pins, guaranteed.