Here is an antique leather-look binder which is made for you to store your certificates. Available in four colour, it is a hard, but padded cover in landscape format, with 4 'O' rings, and will hold up to 40 page pockets (80 certificates if you put them back and front).
Measuring 44.5cm wide x 27cm high (17.5" x 10.75" approx.), it is suitable not only for Australian format certificates, but also the longer English ones. A feature of it is that binder has a small slip-pocket on the spine for you to label it if you wish, and when open, the binder lays flat.
It is a safe archival storage binder for your precious birth, marriage and death certificates.
The binder is sold buy itself, so you may wish to purchase some of the certificate polypages to go in it.