Some very dirty math: According to the wiki, BBCAN10 had ratings of ~850-950k around this episode 5-8 timeframe, accounting for +7 day catchup viewership. Meanwhile, the finale of BBCAN10 ended up getting
674k viewers overnight and rose to 835k in +7 day catchup, so let’s assume that catchup numbers add ~150k to viewership (let’s say 200k to be lenient, since digital watchers grow every year).
Putting together BBCan11’s rating of 464k overnight + 200k I’d estimate viewership at 664k accounting for 7 day catchup under optimal circumstances, which is at bare minimum a couple hundred thousand less than the ~850-950k range BBCAN10 was getting around this time.