Well, quite, Sproink 
I was just replying to someone who said £35 would barely fund one night out.
I think 35 is quite hard to live on if you are in self catering accommodation. My ds spends more that that on food per week.
Of course your could spend that, but there is no need. my dd doesn't spend anywhere near that on food. That's not because she is a petite, eat nothing kind of a gal, she's a sports loving, active hungry kind of a girl but she does know how to cook. My ds is over 6 foot and rugby player shaped, and he managed fine on that too. Both reckon they only spend around £17 / £18 on food / supermarket stuff.
Not sure what you want us to say Hollow. We settled on £35 (well started with £30 for ds, 5 yrs ago) after asking 3 x dns who were at universities or just graduated when he was starting - all reckoned they spend less than £20 a week on food (+ other stuff they'd buy in the supermarkets). Make stuff with mince, makes stews, bake potatoes, cook eggs, make pasta dishes, make curries, thick soups. Yes, learn when you can pick up bargains at the supermarket or shop at Aldi or Lidl. Cook with friends or make something and freeze the spare meals.
Laundry - these day in most student houses they are inclusive of bills, and include washing machines and even tumble driers. They don't have to print that much - neither of mine have had their own printers. Text books are in the library (Univ libraries are open 24/7 nowadays), and lots of relevant stuff available on line, or if a specific article needed, they tend to put them on the University intranet - so buying text books' is hardly a weekly expense.
Clubs and societies are free at dd's University. The one we looked round today for dc3 they each cost £5 for the whole year - so again, not a major weekly expense.
Haircuts - they tend to only need one during term time and sneak in to me paying my mobile hairdresser when home.
Clothes - new clothes hardly a necessity. Something specific they can ask for for Christmas / Birthdays, but they all went with a full wardrobe of clothes - it's hardly a necessary or weekly spend. SO if you need new shoes or underwear or whatever, again, it is spread over the year, not a weekly expense.
Entertainment - well, that comes out of their earnings if they want to spend more than what they have left from what we give them.
However, as others have said, there are all sorts of budgets that different students have. Quite often, the 'cash rich' are the ones on the full maintenance loan, my dc say. But there are lots where separated parents mean they have money due to one parents income and then the other parent gives them cash every month. Or, like, others have said, Grandparents help out / send extra.