At the 'Confirm Your Order' stage of your enrolment online, you can enter a coupon code. See the diagram below;
Click on 'Add a coupon' - you will then get a prompt to enter the code. If successfull, you will be able to see that a discount has been applied. Check the total cost - this is what you will be charged once you Continue to the payment.
Be sure to read over the Terms and Conditions - we cannot issue refunds on the basis that a coupon code was not entered.