Oh, OZ. Sorry to hear about that, my condolences. <VBG>
Surely, you've got some kind of equivalent? Some big-box buying
club or company known for selling things relabelled as their own?
The $22 for a 7AH AGM is quite comparable to the price
in USD for the same thing here. Batteries of all kinds here often have a 2:1 difference in price
for the exact same battery from different vendors. Unless you've got, what? Stiff tariffs or excise taxes
on car batteries?
Another niche is to try contacting a local amateur radio
club. There's often someone in the local utility company who gives them two-year-old deep cycle batteries FOR FREE, or dirt cheap
, because the backup power batteries have to be changed every second year even if they've not been used. That's not new, but often is in very good condition.