I am a carer for my parents so on a very low income, I have never received CMS as ex H disappeared off the face of the earth after an acrimonious divorce when DD was 10 and DS was 4. Presumably he is either hiding under a rock or moved abroad as CMS could not trace him.
My partner and I have been together many years but are not married, he had debts to pay off from before we met and his own children to support as well as our mortgage/bills, as such his outgoings were high despite his good salary. When DD went to uni she only qualified for the basic maintenance loan because of his salary which did not cover her rent yet alone food etc.
She was completing a course at a uni that does not encourage students to work as they have an immense workload and often have supervisions swapped about at short notice including weekends so any free time was different every week. She was also only resident for 10 weeks each term and we could not afford rolling rent so she had to move in and out of her accommodation at the beginning and end of each term. This made part time jobs impossible to get. She put her name down for in college bar jobs etc but their was always a wait list and was unsuccessful.
She secured work in her first year summer break, her second year summer break involved paid internships in London which meant her money earned went on rent and food.
I couldn't contribute towards DD's shortfall in finances as I simply didn't have the means. DP was great and said even if we lived hand to mouth we had to help DD with this opportunity and he paid for her rent, college charges and books each year (£5000) and she lived off her loan (worked out at about £75 p/w).
It really was a financial stretch and we breathed a sigh of relief when she graduated. There were some sticky patches like when our boiler broke down when we were really panicking.
Our situation has now thankfully considerably improved so we are saving money each month for when DS goes to uni next year.
The system has lots of flaws and basing an adult students loan on a household income that includes salaries of people who may have no financial responsibility towards that student is unfair. I have a friend who had to postpone moving in and marrying her partner for 7 years until her DC had all graduated. I have no idea how people with multiple DC's at uni at the same time cope either.