Nudibranch Flabellina ischitana
Hirano & Thompson, 1990.
I am pretty sure this is Flabellina ischitana. Another species which is of similar colour and has the cerata arranged on a common stalk like this is F. affinis. However in that species there is an opaque purple band around the cerata, just below the white tip, which can't be seen in this photo.
Australian Museum, Sydney