Okay, thank you for all your help on this and your great responsiveness!
Matt
Thank you for getting back to me. Here is one of our product pages with Funnel Kit Side Cart: https://www.mailcase.com/product/bronze-mailcase-locking-mailbox/ Click “ADD TO CART” and the Side Cart will pop out. It is this page that we want to disable WP Armour. For some reason there is a conflict with Side Cart and WP Armour so that the Express checkout options in Side Cart don’t work when WP Armour is active. Please note I have deactivated WP Armour for now.
Here is the checkout page: https://www.mailcase.com/checkout/
Thank you!
Matt