I did this - but it was actually line 55 of the paypal code as I moved the paypal code before the authorized.net code as suggested earlier.
This does not work unfortunately as changing the code refers the cart.php directly to the paypal checkout without even opening the checkout.php page.
I will attach a copy of the changed confirm.php page to this post but I have changed the code (line 55) back to the previous as I need to have the checkout page come up.
Any other thoughts?