The shutterply wrapped in white apparently there is no stock in The country . The cabinet makers that work with us on site use it for the basin vanities and kitchen sink units . I was told they get it from china and suppliers are waiting for stock to arrive. There is another melamine that is waterproof. Not sure what they call it though . But i wouldnt use it on a tank cabinet.
I used normal shutterply and stained it to the colour i wanted then painted it with a clear polyurethane varnish .
The ply you refer to is called mellaply and is readily available here in Durban only available in a matt white though... Another option is to get standard MDF and ask for it to be double wrapped. Similar to kitchen cupboards. Will be more durable and you get tonnes of colours.
Or use marine ply. Then seal it fine sand it and spray paint it. If you using ply or superwood make sure you seal it 1st. That way your wood wont swell ect. Best option is marine ply with a little work it can be perfect and will last forever.