Broke PHP Contact form using .htaccess Clean URLS

Using the contact form code from the PHP Simple Application Course

It was all working wonderfully until I decided to clean up the URL's with .htaccess

Here's my htaccess code.

# REWRITES
# Canonical
RewriteEngine on
#RewriteCond %{HTTP_HOST} ^site\.co.uk$ [NC] RewriteRule ^(.*)$ http://www.site.co.uk/$1 [R=301,L] RewriteCond %{THE_REQUEST} ^.*/index.html
#RewriteRule ^(.*)index.php$ http://www.site.co.uk/$1 [R=301,L]

#prettyurls
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^\.]+)$ $1.php [NC,L]

#index to root
RewriteCond %{THE_REQUEST} ^.*/index\.php 
RewriteRule ^(.*)index.php$ /$1 [R=301,L]

This has since broken the submit, when I submit the form it comes back to site/contact and the page is blank.

Previously it would append the contact.php with php?status=thanks and change the message with the if statement as normal.

I've tried removing the php part here

    header("Location: contact.php?status=thanks");
    exit;
}

//Changed the above to this
    header("Location: contact?status=thanks");
    exit;
}

Do I need some kind of negator? The URLs work with or without the .php and I've tried starting the page as contact.php too, so it can go back to .php, but it always ends up at /contact without the php extension and a blank page.

Any help would be much appreciated :)