Hi Jason. Many thanks for all your work so far. On testing the site I note that the PayPal gateway is now working correctly and I am returned correctly to the site via the checkout_success.php. I do note quite a large amount of additional information but am presuming this is just a display of hidden information for testing purposes. I have attached a PDF capture of the page for your reference.
The EWay payment gateway is now processing the payment correctly but unfortunately appears to freeze on their eway.com.au/gateway/checkout_sucess page and I am not returned to my own site. I did receive a payment conformation email from eWay but nothing similar from my site.