Kane, yes that is likely a beaver tail allthough you can't see in the photo how well defined it is.
So there were three, maybe even four supercells the 10th as it looks like a possible fourth near Nambucca Heads. James i'm taking was on the Grafton cell and MB on the northern most cell. So i'm asumming that the cell near Coffs was pretty much unseen apart from Kanes pics.
Some great structure from all cells on both days, and yesterdays cell, what a beast to top it off.
Regards Jeff.