Section background not showing on Mobile

I am having is that if you go to hcldesign.co.uk and go to the ‘about me’ section further down on this page you can see I have a wood backing set to ‘fixed’… now when I go onto a phone or tablet this wood backing to the about me section is not visible. I have tried to change the media query but it doesn’t seem to make any effect. Any idea in what needs to be changed here or what CSS I can add to fix this so the wood backing shows on all devices? (It shows fine in a browser window if any size, but not on a phone or tablet)

Thanks

Harvey

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