I remember finding a shop in the UK where they sell some, had to look it up but here you are: https://www.nextdaybullion.co.uk/products/gold/goldbacks/
They don't come with a cert btw, I think you can find all the info on the bill. I haven't ever seen a cert added to be honest..
RE: 2025 Florida 1/2 Goldback - Alpha Edition