We have gone through each warning and error on the site and resolved the following issues:

Directed traffic to correct page URL’s – some were showing 404 errors
Take out images that couldn’t re-direct to any page and add correct ones.
Make sure all products and pages have H1 headings
Made sure all meta titles were a good length, not too long or short
Made sure every page, product or category had a meta description
Updated all alt tags
Made sure all pages have internal linking that uses the right URLs

The dev team will get the rest of the warnings sorted soon, which will include improving site speed, making sure Javascript is compressed and cached, and the same with the CSS