No 5.1 on the Blu-ray, but I didn’t see a thread and thought it would be of interest to some people:
https://superdeluxeedition.com/news/faces-at-the-bbc-complete-concert-session-recordings-1970-1973/
https://superdeluxeedition.com/news/faces-at-the-bbc-complete-concert-session-recordings-1970-1973/