How to remove social buttons linked to squarespace from header

Hello,

I cannot seem to work out how to remove three links in my header that when clicked direct you to squarespace's social pages. There is no option to remove them in the design and page layout as far as I can see, only to add more buttons such as email etc. screenshot attached and I have also made the site public for now www.mondo-advisory.com 

Any help much appreciated!

The Facebook/LinkedIn/Twitter links are in the navigation. You will find them in your dashboard in the Pages menu under main navigation. They will appear as links.