Hi! I'm not in the UK, but I am in the states, and I am also in my final year at a university.
I am doing a SUPER intense/restrictive diet, and I struggle every day with making the correct choices... I cannot eat in the cafeteria most days, and I cannot partake at parties because most foods I cannot eat, so it's actually a blessing to be on such a restrictive diet, knowing and telling myself I CAN'T eat or drink those things....
I wish you the best of luck! You'll have to put yourself into a mindset of what goal you want, and just stick with it... Tell you friends what you are doing, it may seem embarassing, but I promise you, if they are your true friends, they will be supportive and help you out along the way.... Ask them to keep you accountable, and to not tempt you, and hopefully they are loyal and will be good support for you.
Best of luck and I know you can do it! It will just take a lot of willpower!