The blank lines were coming from some Banner code that was being generated on the pages. I went through all of the settings for the theme and the only reference to a banner was under the Home Page Slider. There was a tick box for the option “Do you want to display the static banner image ?” I unticked the option and now the pages appear ok. Not sure how this option affected the non-home pages and why it started causing the problem all of a sudden. In any event that’s the solution. Just untick that box.
