Hi Craig,
Nice looking car.
I have x type and did have S type, so can only tell you what I read.
Xf before 2010,only real reports occasionally seem to be faults with wiring in boot, affecting it closing and brake lights
Warning lights stuck on, sat nav going off, cosmetic problems door trim loose.
fuel cap jammed
a few cases of turbo/air con problems but problems seem to occur well after 100k.
but really seems a decent reliable car.
enjoy!