Thanks for replying.
The client is using Paypal payments standard.
Can you confirm where the IPN should be pointing to once payment complete? I assumed this was working fine as after payment had been processed it returned me to the correct page on the site.
I have tested again and I am taken back to an order confirmation screen where it has allocated an order number and sys a receipt will be emailed to me but no receipt and still no entry into the database regarding the order.
Another thing I have noticed obviously since there are no orders in the database is that the statistics are showing that no products have been sold through the site even though I have processed a few test live purchases.