So I ended up choosing NRMA.
$800 basic excess. $400 age excess. Excess-free windscreen and extra hire car cover.
Premium is $200/month..ish. It should go down a lot when I turn 21 next May so I only have to cop a high premium until then.
Looks like I will have sold my SP23 by wednesday/thursday next week and can pick up the new beast on the 29th