Geekraver, I did have something in the HTMLTIDY box, that sorted it, thank you!
However, I do have another issue (tell me to go away if you like!) The HTMLDOC PDF's get generated fine - but without the table of contents. When I output in HTML and run it through HTMLDOC manually, I do get a TOC... It may be that (knowing me!) I've changed/deleted something in the HTMLDOC options box - what's the default supposed to be?
Many thanks for your help