That's what I would have thought, however there isn't a session value showing in the confirmation email. If I open the cart page I can see the cart session values and there's one called [Present Discount Title], however if I echo that on the email page it just gives me the first of the discount codes set up, not the one that's been used:
<?php echo $VetProCart->RuleLooperName("Discounts"); ?>
There are also cart session values for each individual discount code I have set up, for example:
<?php echo $VetProCart->GetRuleValueByName("Discounts", urldecode("discountcodename")); ?>
but I'm not sure how I would use these to only display the one that's been used?