Thanks
@RichardMEL. I did consider booking OOL>SYD the day after, but was thinking it would likely be ok. The original plan was simply AKL>MEL>OOL, however I then noticed I could do AKL>SYD>MEL>OOL for similar cost and a decent bump in (D)SC, so it was a no-brainer in that respect. In fact, ironically the latter routing provided greater buffer for the OOL>SYD flight. The longer I've had it booked, the more concerned I became about that 30m connection in MEL. I'm sure it will all work out fine... I was just contemplating approaches to minimise issues if the worst happened.
In summary, I guess I'm hearing that there's not much point in trying to link the bookings.