Quote Originally Posted by Steven300 View Post
First of all, I was wondering if someone could explain to me what the PDT Token is. I know that it has something to do with speeding up transactions and I know that it can be copied and pasted from PayPal to Zen Cart admin but I don't know much else about it. Do I need it to be able to complete a transaction?
PDT allows Zen Cart to talk to PayPal and confirm that payment was received without having to wait for the normal IPN notification to be sent to your store from PayPal.
Sometimes the IPN process can be delayed and unreliable. Enabling PDT can sometimes alleviate the pain associated with the delays.
However, it's not 'required'.

Quote Originally Posted by Steven300 View Post
Also, what actual difference (if any) does it make between using the default www.paypal.com/cgi-bin/webscr and changing it to www.paypal.com/uk/cgi-bin/webscr. I am in the UK and only plan to sell to UK customers so should I change it to the UK one or can I leave it as it is?
Nowadays, as far as I can tell, the difference is minimal, if any.
It used to be necessary to ensure your transactions were hitting the correct servers for processing.
Nowadays I'm pretty sure it's not important.

Quote Originally Posted by Steven300 View Post
Lastly, what exactly is the refund order status. Is that when someone starts an order, goes to PayPal but changes their mind at the PayPal stage? Its status is currently set to 'Pending[1]'. Has anyone changed it to something else more descriptive?
If someone places an order and pays for it via PayPal, and then you later go and refund all or part of that payment, your order's status will be switched to whichever status you have the Refund Order Status set to, when the Refund IPN notification from PayPal's server is sent to your server.