Assuming David Gemmell is listed as the first author:
Code:
{authors:sublist(0,1,&)||/}{series} {series_index:0>2s} - {title} - {authors} - {isbn}
P.S. I'm not actually sure what the separator is for multiple authors (although I remember it being &). I don't really have books with multiple authors. Neither have I added any series info yet. I just use the sublist function for tags (comma separator) so my Save to Disk looks like this for now:
Code:
{tags:sublist(0,1,\,)||/}{authors:'re(transliterate($),"[^A-Za-z0-9&-_ ]","")'|| - }{title:'re(transliterate($),"[^A-Za-z0-9&-_ ]","")'}