I believe this question is more suited to serverfault (please correct me if not).

This issue appears very similar to this question (except there are no 301 Moved Permanently for any pages). The domain is yorkshirebadges.co.uk.

For example, loading yorkshirebadges.co.uk or yorkshirebadges.co.uk/index.php reports no 404s during network inspection. But every other page (/contact.php, /products.php) report a not found.

Mod_rewrite is being used on the site, I checked this out but didn't see any obvious errors. It's included below for reference:

RewriteEngine on
RewriteRule ^store/material/([^/\.]+)/price/?([^/\.]+)?$ products.php?prodType=$1&price=$2
RewriteRule ^store/price/?([^/\.]+)?$ products.php?price=$1;
RewriteRule ^store/material/?([^/\.]+)?$ products.php?prodType=$1
RewriteRule ^store/([^/\.]+)/?$ products.php?prodCat=$1
RewriteRule ^store/([^/\.]+)/price/([^/\.]+)$ products.php?prodCat=$1&price=$2
RewriteRule ^store/Type/?([^/\.]+) products.php?prodType=$1
RewriteRule ^store/([^/\.]+)/?([^/\.]+)?$ view-product-details.php?cat=$1&prodName=$2
RewriteRule ^store/([^/\.]+)/material/?([^/\.]+)?$ products.php?prodCat=$1&prodType=$2
RewriteRule analytics http://www.google.com/analytics

<IfModule mod_suphp.c>
  suPHP_ConfigPath /home/yorkshir
<Files php.ini>
  order allow,deny
  deny from all
</Files>
</IfModule>

Chrome Network Inspection (and firebug on firefox) report 404s on all pages except the index, the server is apache2.

Really scratching my head on this one!