Hypothetical: A UK company advertises a service and promises a free gift for new subscribers. I enter the service contract with the company as a private individual and get the "free" gift. The gift fails after a year in a way that would be covered under warranty if I had purchased the gift from a retailer. Is the company required to honor warranty? Can they just decide to issue a £0 refund?
I assume the answer is "it depends on the nature of the service contract, the gift, and the advertisement", thus my question is: what are the rules?