Hiya
You need approx a 28-30 tooth blade at 315mm dia, I use a few makes but quite like Freud as a good blend of quality and price but the Xcaliber brand from Axminster look OK. Also there is a chap on here with a business called Cutting Solutions who can supply at a good price and also advise in more detail. I think his forum name is cuttingsolutions as well.
HTH