The Mazda Dealer Parts Interpreter looked them up and said there are 32 to a side (there are 12 as far as I can see) and they don't keep them in stock but I could order them from Melbourne.
Supacheap have the Champion 4-pack for $7. but they don't fit (bought a pack and tried them - totally wrong size - see photo)

I then called at the biggest smash repair business in town. The Foreman said they don't have anything like that. "We have Toyota ones but they are not the same". Mazdas apparently don't have crashes.
So looks like I order a half dozen from the Mazda Dealer.