27 year old first-year Law student here!
Alongside a maintenence loan (I currently receive the maximum amount which is a little over £3,000 every three months, deposited three times per school year) I did have a weekend job for Saturday & Sundays however I recently left it so I can fully focus on my studies.
I am on the books for a local bar/restaurant for overtime during school breaks so I can make up savings (My uni breaks mid May and isn't back until September so that's almost four months of full-time work so can make about £7,000 during this period as min-wage for my age is about £11ph.) Add in all the weeks off here and there such as Christmas break (6 weeks off) spring break (4 weeks off), your average wage isn't too bad if you're pulling shifts over these breaks.
If you can maintain a weekend job alongside your uni, good on you. I might go back to one Saturday, but uni really is a full-time job in itself. I have lectures or seminars everyday of the week, and I stay all day at university as I achieve way more on campus than I do at home.
Returning to uni as a mature student - especially when living with someone else - requires a lot of budget planning and open communication on expectations.
If you want to ask any questions, please just let me know!