First of all, go to https://www.helpspace.org.uk/login and log in to your account. 

Once logged in, you should see a menu item 'Billing History' in the main menu. Click this to view your billing history.

If you do not see this, it is possible that you are still viewing the 'public' area (as opposed to your account area). Look for a green button in the main menu that says 'Dashboard' and click it. This should bring you to your account area, where you can view your billing history.