Thanks but I've checked out that plugin and it doesn't do what I need. The plugin gives me a widget and a signup tab, whereas I am wanting to put the signup form into a templated homepage (i.e. not a standard page + sidebar).
The theme I am currently using is Kraken - like many themes it has a home page template. I can insert the php for the 'tab' signup option but want to know how to embed the signup form into the page.
Check out the homepage in the demo:
Where there are three 'service' areas beneath the slider, I'd like to make one of these into a space for the form.
I get that this sounds really theme-specific, and I've asked the theme creator too, but it's not just an issue for this theme, I really would like to know how to do this on any WP theme.