Thank you for your replies, and thank you John712 for your generous offer, but if Eddy is correct and I would need your password(s) I would never expect that.
After a little more research (which I should have done before I posted) the $AU fee is $49.99 (save $20) so if you have auto-renewal enabled it seems you are charged the highest amount possible, which is not a good way to look after your existing customers. That being the case there is no point in trying to be loyal and have auto-renewal enabled if all that means is that you are going to be charged higher rates than anyone else. I am not happy that they do this, so as I said when my current subscription expires I will get the free Avast antivirus. I will still be a paying customer with my Secureline VPN, which I like.
Surely existing customers should expect and deserve to get the cheapest prices that are available to everyone else, without having to check to make sure.