As did my dad. The rear inboard brakes killed it irrc!
A pal owned one and said replacing the
rear pads was a big pain in the arse. He ended up paying fifty quid (when that was quite a lot of money - eg same cost as a rebuilt gearbox from my Cortina at the time) for a special pliers from BL. He then discovered that it didn't work if they were 90% worn or a bit rusty so he still needed to take much more apart than he wanted to.
Another guy I knew, who incidentally also had a pristine P3, said you "just" needed to unbolt the diff from the floor pan which gave you the access needed for the brake pads.
By way of explanation, the P6 had a de Dion axle where, unlike true independant rear suspension, there is an axle tube connecting the wheels, but the diff is fixed to the body and drives via IRS like half-shafts. To further reduce unsprung weight (a good thing to do) they stuck the discs on the in-board end of the half shafts. Great for handling/roadholding but bad for maintenance
I once had the privilege of having a go in a P6; an auto V8 in quite poor condition which my then boss had just inherited from his grandad. It felt like it was on rails compared to my slidey sloppy (though to be fair predictable) Mk 2 Cortina; a much lesser car of similar age. It went rather well compared to the 60hp Ford too