Let me offer some clarification to my question:
When using wordpress and datafeedr a "store" tab is created in wordpress as a permalink. You can then use the datafeedr plugin to import your categories.
I was wondering rather than have the "store" button is it possible to have a button at the top of the page for each parent category (replacing the store button)?
Then once you have a list of parent categories running horizontally across the top of the page I would like to "hover" the mouse over these parent categories to "reveal" the sub-categories.
I hope this adds further clarification?