Coupons and Free Shipping

I have added Coupon Codes on Woo Commerce – these are relevant to Gift Cards people have purchased. I am trying to allow the Coupon Code to be used against any shipping cost, is this possible?
As a work around I have changed the coupon code amount and added free shipping but it still doesn’t show up as free shipping and is trying to charge this.
Please help!

The page I need help with: [log in to see the link]