Ok, I think I am getting somewhere now. When I remove the tiff preview option, it works just fine. So it seems like it works if the original doesn't have a -tiff attached to it. (I like the preview for when i import the graphic in a WYSIWYG word processor).
I tried using the script to improve my matlab-generated eps files (created using print('-depsc2','-tiff','-r600','filename.eps'])), but the output file cannot be read by ghostview.
I get the following message "DOS EPS header is bad". Ignoring DSC comments" in GV.
The Adobe Distiller-generated PDF for the eps file is a blank page.
Although, I do think it would be good to put in a warning if tiff preview is activated in the file being processed. It seems that a flaw which removes plot lines would be something of which the user should be made aware (along with the quick solution)!