Nick, I hate to have to curb your enthusiasm, but under UK law you can\'t enter into a contract as you are under 18, which by accepting commissions is what you are doing.
Neither you nor your potential customers would be protected if something went wrong.
Plus (and I\'m not 100% sure on this) I believe you\'d have to declare this as a part time employment to your local Education Youth Employment officer. (The rules are a bit complex).