Hi @b43,
Welcome to the Bunnings Workshop community, it is wonderful to have you with us.
Is the basin porcelain? If not, can you let me know what you think it is made of?
Assuming it is porcelain, I'd suggest you start by cleaning it with a cream cleaner such as Jif Professional Lemon Cream Cleanser. Apply to the basin with a damp cloth, give it a bit of a scrub then clean away with clean water.
Once clean and dry, you can use this Rust-Oleum 13.3ml White Tub And Tile Touch Up Kit to recoat the damaged surface. This is a two-part epoxy product, designed for chip and scratch repairs to things like basins, baths and tiles. It should be perfect for filling in those slightly damaged areas.
Let me know what you think and if you have further questions, please don't hesitate to ask.
Jacob
