Error - We were unable to retrieve your Facebook account information.

I know we've discussed this before, and I remember your strange issue where the misconfiguration is always showing.. but when I go to your actual application page on Facebook:
www.facebook.com/calendarised
The link for "Go To App", which should take you to your website, is instead taking you to some other page on Facebook which is asking for a bunch of permissions (access data anytime, birthday, events, etc). Your application Site URL and Domain URL should be pointing to calenadarised.co.uk, and if not, you won't be able to use the Login With Facebook button on those pages because Facebook won't think they're related.

If you can give me more information on how your app is configured, that may help. Finally, when I try to login on your site, I get the generic "Unexpected Error Occurred". However, if you hit the button while logged into another tab with a Facebook user who's an admin for your app, they should get a more specific message about the error that's only shown to admins. If you can tell us that, it'd help.

Thanks,
Alex

Mike,
For our upcoming 4.0 release (later this month), we're integrating a few App/Website as Tab and Canvas features, so we've been doing a bit of testing in this area lately.. and hopefully, you'll like some of the new features you'll have at your disposal when using your website within Facebook as well.

In our development, we've been testing quite a bit of the configuration settings, and I actually think you'd want to have the following setup:
Site URL: calendarised.co.uk/
Domain URL: calendarised.co.uk

Canvas URL (if using this feature): calendarised.co.uk/ (or whatever page you want as the main canvas landing page)
Tab URL: calendarised.co.uk/

When viewing your page in Facebook, FB actually will scan and intercept the calls for Logging in and Logging out so that it can automatically approve requests or 'see' the current user logged in. It's a benefit of being run inside Facebook, but I think you still want your app setup, in general, to be run outside of Facebook on your main site.

Try those settings, and see if you have more luck. If not, let us know, and we'll see what we can do.

Thanks,
Alex