However, we all know that parents and grandparents contribute to their offspring's expenses, which puts those from poorer families at a disadvantage. On the other hand, I also knew students who claimed on the basis of a divorced parent's income, but received support from the other parent and/or grandparents.
With the best will in the world, those from poorer families are always going to be disadvantaged, financially at least. The grant system was never intended to sort that out - that would take an overhaul of everything, and is way outside the remit of this thread.
I don't think that students can play the divorced parent trick nowadays (and I also remember people doing nicely out of this), as both parents have to declare their earnings and the awards are based on the total. When my children were going through the student loan system my husband and I each had to do separate sets of forms, even though we are married and live together.
I believe in individual taxation linked to the rights to benefits (and I mean benefits in the loosest sense here - the benefits of living in a rich economy, rather than subsistence benefits for the poor), and I think that this should start at the age of 18.