Widget non ajax

Hi
I have two forms on a site
One, on the front page, works well
The other is a widget, made from putting the shortcode in a text widget
With this one the page refreshes when the button is clicked and doesnt appear to work
You can see that one here
http://southlondonpacific.com/tikipress/contact-us/
Any suggestions
Many thanks for a clean and simple plugin
Oli

https://wordpress.org/plugins/easy-peasy-mailchimp-ajax-form/