Multiple discount codes
If a booker has two different valid discount codes and tries to apply both at checkout, the system will automatically decide which discount code gives the booker a better deal, and apply only that code. It's not possible to use multiple discount codes when booking on Bookwhen.
Discount code + Block booking discount
As in the example above, if a block booking discount is automatically applied to the basket, and the booker then adds in a discount code, the system will automatically detect the better deal and only apply this. It's not possible for a customer to use a block booking discount and a discount code at the same time.