Thanks that's just what I needed, I can always count on the forums for a fix!
This is what I did:
Edit Paypal.php (Includes>Modules>Payments>Paypal.php)
Search for
$this->form_action_url = 'https://secure.paypal.com/cgi-bin/webscr';
Changeto
$this->form_action_url = 'https://www.paypal.com/cgi-bin/webscr';