Doesn't matter what theme I try if I visit "myblog/archives/000001.html"
there is a link at the nottom of the page that says
"/index.phparchives/000001.html/page/2/" "previous posts Â»"
^ note the missing slash
This is because the permalink structure I was using was the non mod_rewrite version, so had the /index.php prefix.
Guess this is a very minor bug...