I am in the same position as you - Son started univerisity last September and I lost £66 a week tax credits - my daughter will start this September and as I work less than 30 hours a week , with no hope of increasing my hours, my child tax credits for her and my working tax credits for me will all stop - yet my rent doesn't drop by 2/3 and nor do my bills.
I have to keep a 3 bedroom house going on one shop workers income - don't know how I am going to manage - they will have to pay me some rent when they come home over the summer holidays, as student finance has to cover them for the whole year - fact of life - in the real world people don't get 3 months holiday - so they either budget for their keep out of their student finance money or get a summer job (easier said than done) - either way at my age I will probably be reduced to that student staple of eating Asda smart price 9p noodles!