2 Sidebars break site

Problem with RESPONSIVE classifieds theme – see attached – sidebars broken moving under main content and sending INLINE home page element to display FULL width

have tried disabling full width slider – same
tries using half width slider – slides still go full width / distort = a real mess

theme using 3 column layout – very confusing – can’t seem to find why its doing it (not all the time either ) once i’ve gone in a resaved home page displays to INLINE it sometimes goes back into place. Next time i visit home page its broken again ?

Client getting a bit panicky as we’re publishing end of this week

help!

last major css change customisation done (via DT dash) was full width logo in header – could this be breaking the site?