All .php files are 403 Forbidden + No 404 Doc Found - php

Question

Had our website up for a while, and I'm now working on a contact form with a simple PHP mailer. For some reason though, all .php files on the directory are 403 Forbidden. For example:
http://www.bawkdesign.co.uk/mailer.php
Even trying .php files that don't exists results in a 403.
http://www.bawkdesign.co.uk/idonoexist.php
Perhaps there's something in .htaccess causing this? If there is I can't see it! The website is hosted with GoDaddy (Yup, not my choice)
I've checked the file and folder permissions and they all seem good too. Any help is really appreciated.
.htaccess file
#Rewrite urls to remove extensions
Options FollowSymLinks
Options -MultiViews
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^\.]+)$ $1.html [NC]
RewriteRule ^(.+[^/])/$ http://%{HTTP_HOST}/$1/ [R=301,L]
RewriteCond %{HTTP_HOST} ^bawkdesign.com [NC]
RewriteRule ^(.*)$ http://www.bawkdesign.com/$1 [L,R=301]
#404 Page Not Found
ErrorDocument 404 /404
#Enable server side compression
AddOutputFilterByType DEFLATE text/text text/html text/php text/plain text/xml text/css application/x-javascript application/javascript
#Enable Mod_Expires for browser caching
ExpiresActive On
ExpiresDefault A0
# Set timing for cached files to expire after
<FilesMatch "\.(jpg|jpeg|png|gif|txt|xml|php|js|css|html)$">
ExpiresDefault A704800
Header append Cache-Control "public"
</FilesMatch>
#Define the charset
AddDefaultCharset utf-8