Finishing painted furniture

I’m painting a piece of furniture and I’m not sure what my options for top coat are. From what I’ve read polyurethane yellows. There’s a U.S product called polycrylic. Does anyone know what the Australian alternative is or what else I can use? Thanks

I see it’s been a while since this thread was active, but for anyone still seeking solutions on where to buy sandpaper, you can visit https://priorypolishes.co.uk/product-category/sand-paper/. They offer a variety of grits which meet various sanding needs.