Responsive Header Problem

Hello,

I’m having an issue with the inner pages header, when I choose to use a featured page image. I upload an image of 1920×800 but the image doesn’t fully show, and doesn’t re-scale when changing window size on Desktop or when viewing on mobile. This causes a lot of the image to become hidden.

I have no issue changing the header vertical dimensions using Customizer but the image seems to be scaled to the window height not the header size.

Can anyone help please?

Thank you.

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