IEC Question - British Citizen

[Danh]

I will be going over without an IEC shortly and am still waiting for the confirmation letter - which seems delayed. I am a UK citizen and have booked flights to return just over 6 months. My first question is - Will I have to prove that I have a returning flight within 6 months? Will I have to prove I have sufficient money to live on for 6 months? Can I also use an external source i.e the parents to guarantee for some of the funds?

Thanks for the help in advanced.