Car Insurance for young driver (UK)?

Hi im 17 and a male from the UK. I take my test next friday (Cant wait) If I pass, I want to be insured a few weeks after. I understand I will be paying about 2500 - 3k. Is there anyway at all to bring it down? Im going for a 1L I think. Could I possibly use a family who im related to who have been driving for years? As a additional driver or something its called right? Just any tips to bring it down? Even a couple of hundred. Thanks for any help.