Is this classed as multiple entry or just 1 as not sure if you need a visa for Hong Kong. Also where on the site is forms to pay?

You just need to apply a L type for mainland China. You can enjoy 180 days visa free period in HK. The application form can be downloaded from the top of this page for free. You'd better sign it online and then print it out. It's said that hand-written application forms are no longer accepted.