Page Redraw Slows Site

Hi Flynn,
What a fantastic theme! Would you please look at nctravel.com.au to see why it redraws/refreshes every page, when you choose a new category or to read a post (in IE+Chrome, but not FF) ? This seems to make everything lots slower, however other sites using Atahualpa (privateerwebsolutions.com or creativekidslearningtoys.com) do not redraw/refresh. I'm using Hyper Cache & Ata ver342. I'm not looking forward to redesigning the placement of javascript, etc, if that's what's involved.

Also I'm using "Custom Taxonomies" for the "Choose Hotel" widgets, but when clicked, the sidebars disappear (even when they were left & right). If this is complicated I can put it in the Sidebars forum.