Yep, your current CPU is fairly weak by current standards, however rather than relying purely on the star rating which is flawed, I'd suggest running the game with the setup you want and see how you actually find it. I am going to assume you meant 8GB RAM rather than 8MB!
In terms of your requirements, if you only want to look at Dell laptops, then the best you're going to find under £500 looks like this: https://www.box.co.uk/2V448-Dell-Vostro-15-3515-Ryzen-5-8GB-RAM-256G_4103172.html
If you're happy to look at things other than a Dell, you can something like this which offers better performance for the money than anything Dell is currently offering: https://www.box.co.uk/82LN00DJUK-Lenovo-ideaPad-5-AMD-Ryzen-5-8GB-RAM-256_3746804.html