Just had a pursue at this thread and thought I would offer our experience as we were in this position last year (I'm also a 6th form tutor).
Student finance can be a nightmare; as soon as the window opens I recommend getting the application in. Even if you as parents are not declaring income/or will not allow for more than minimum this needs to be done asap. You don't have to wait until firming as they can put any of their offers and change it later.
As other posters have said, when deciding firm/ insurance, don't bank on unis dropping grades just because they might have done previously and always choose an insurance they would be happy not only studing there but also living there.
Get you DC to join The Student Room - each university has its own forum; information re accommodation etc are answered by those who live/have lived there and this can prove to be invaluable
I would never recommend anyone firming/insuring a place that they have never visited you would be surprised how many do
Have an action plan ready for the summer incase of unexpected results - your DC need to be prepared
Do train them in life skills! My DS reported that 2 of his flat of 6 hadn't any experience of washing, ironing, cooking, shopping and these were the ones who were the most homesick.