I have heard of people doing it too.. That the one up Tongaoi you mean?
Was in at FCO few months back and they told me it a good spot to go and that it best to go there when wind is NW (offshore) for safety unless it a really calm day. Is about a half hour walk around apprently. Also good snapper and gurnard off there too they said..
I have been wanting to go there for a while myself. Maybe time for a mission.. Better in numbers..