Problem solved. Thanks to everyone for your posting.
We’re back in business this morning. i purged the page caches and presto! PDF goodness.
dublin_dara was probably viewing a cached page earlier. looks ok now. arthritis-research-uk-exercise-sheets
Now, let me get this dependence on google services straight. Even though shortcode urls point to files in one’s wordpress media library, actual display of the preview by GDE, in the body of a post, requires the co-operation of google service? while the PDF Embedder plugin does all this independently?