I have 2 DC at uni. 1 is at Cambridge, now in private rental as she's studying for a PhD but was offered college accommodation. In her college, each room has a locked cupboard where you can leave things like crockery, pans, duvet etc during the Christmas and Easter breaks. That meant that I could do 2 pickups on the same day as it all fitted in the car. When she went to uni and for the first 3 years, DH was on NMW trying to get a business off the ground. DDs both got almost full loans which we topped up £100 pm. DD1 at Cambridge also qualified for a Cambridge bursary which pretty much covered her accommodation. However, neither DD has wanted to live in catered accommodation. They have saved a considerable amount by being imaginative and competent in the kitchen.
DD2 is at a uni in the Midlands although is on a gap year, supposedly abroad but is actually back home with us and registered at a uni in Japan. She was in a uni flat until Christmas which cost around £110 per week. She self catered and spent less than £20 per week on food.
Both DDs had weekend jobs from the age of 16. We live in a tourist area so they worked in an ice cream shop doing around 4 hours per week, but in holidays they did as many shifts of 4 - 5 hours as they wanted to. When schoolwork got heavy or there were mocks, the shop was shut for the winter, so it worked well for them.
In short, halls are expensive. Self-catering is normally a cheaper option, especially if you have commitments that run across mealtimes - mine both sing so often have services or rehearsals. Back in the late 1980s, in a northern uni which is now RG, I paid £16.93 pw to live in a 3 bed back to back terraced house. It was a bit grim but gave me the full student experience.