Accessibility – Keyboard navigation

Hi all,

Having a small issue making my website accessible, which is massively important to our company.

http://www.viresourcing.co.uk

The menu at the top of the page works fine when using a mouse, but when you use keyboard navigation to get around the page it will tab over each of the parents menu entries, but there is no way to open the submenus.

Space moves the page 1/2 way down.
Enter does nothing
Arrow keys move the page

I’ve tried looking at various plugins and none are helping. What is the best way for me to code this manually so I can get this to be accessible?

Many thanks,

Stu