HI, If this is the correct one you saw, you can click on the supplier's name to the right of the product to see their full details.

If you look on eBay, leisure coast garden centre, Fairy Meadow nsw , type in large garden pots , they have a really good range and at such good prices and they have similar to what you are after. Good luck

Your question has appeared on the Australian Houzz site. I sympathise about your clay soil. I live in a region with heavy clay soil and brought in special lawn soil for the lawn area. This is the US site https://www.houzz.com  Houzz now also owns Gardenweb which has a specific Lawn Care forum where you should be able to get help with your question. You can find it by going to Stories & Advice at the top of your screen and clicking on Gardenweb Discussions and then going to Explore Topics on the left side of your screen and clicking on Garden Forums where you will see Lawn Care listed. Here is the direct link. https://www.gardenweb.com/discussions/lawns

This isn't a personal recommendation as I have not yet purchased anything from this company, but I've been admiring the timber floating shelves on their website. https://shelvingshop.com.au/product-category/floating-shelves/wood-effect-finish/ Or you can buy the brackets and have the shelf custom made in whatever material and size you want. https://shelvingshop.com.au/product-category/brackets-2/floating-shelving-brackets/  I think hardware stores also sell brackets by themselves. I was thinking of going the custom route because that means I can ensure the brackets will be attached to the studs. I believe you can paint melamine after proper preparation of the surface, but I doubt if you can stain it.