A very late reply to this, I was searching for something else. Hopefully better late than never.
I was there, but funnily enough don't recall the Faces playing at all. The weather was hot and I remember Marc Bolan cross-legged on the front of the stage. He was in transition between the elf and the glam rock god phases and played a mixed electric/acoustic set. Robert Plant was there with his wife and child just to listen. Lots of people, but not uncomfortable or crushed.
The event ran massively overtime, the last band to play was Edgar Broughton and the plug was literally pulled out by the venue mid-set at sometime after 11:30pm. If the Faces were headlining, they may not even have got on stage, which might be one reason that I don't remember them (amongst many other things!). I remember leaving the castle with the whole crowd singing "out demons out", very good natured event.