Ive been knocking around with this for a while now and actually think the best solution is to use the menus with sub pages that drop down. I have an existing structure to my site and am developing the Epik theme to fit on a test site before going live. THis was one of the main issues in converting my site with a lot as many as four pages with groups of sub pages to organise.
So fingers crossed, I have given up with the epik portfolio, portfolio plugins and basic html (because of the issues with responsiveness). A menu system is the most sensible for me for now I think. Hope that helps.