What are the terms and conditions of your promotions? 21 June 2019 09:44 Please see our Terms of Sale (Clause 11) for any information on ghdhair.com promotions. Related articles Can I use my promotional code with another offer? I am seeing a message that says my code is invalid, what does this mean? Do you advise in advance of your promotions? Do you offer NHS discount? Do you offer student discount?