We've found the lack of public jetties & mooring options to be a hassle in the past, although it has been a few years since we sailed into Bunbury.
KBSC - I've found them VERY helpful, but the club is not always open / manned. If you can get in touch with them in advance of arriving I'm sure they can put in place something or else advise where you can moor.
All the best
Poods