I am making a lifestyle app. I'd like the user to agree to some usage terms and conditions before they can access any of its functionality (i.e. asking them to use it appropriately and not do something daft they fancy suing over later).
Do I need to make a record (i.e. as persistent data) of the user agreeing to the T&Cs? Are there any Apple guidelines specifically about this?
No, you do not have to record this, because you can (later) in a court of law to prove that any user can not reach these features without agreeing to terms & conditions. so you are not liable.
In this case, Apple does not have any guidelines for this, because you will not record user's actions.