those renewal notices often are scams. i get those per snail mail once a year from some obscure us address but i my domains get handled by my webhoster.
The timing's right, and I've always completed the renewals at AustDomains.com.au. Also, I remember having to sign up for them right near the beginning. So I think they're legit, and just a complete rip-off. It appears quite a few similar Australian services are quite expensive.
Jibb
