Hi again.
Student Finance If you call them you might get a rough idea of what might happen financially.
You fill in a form and this gets you access to grants and loans and childcare costs. Also look at the Uni's you'll apply to and see if they have any grants you can apply to. Some charities have grants and scholarships (google them). DP applied for everything and got a scholarship based on previous academic excellence, but there are others available, obviously competitive.
DP did A'Levels prior to applying, not just for the course, but to see what studying at such an advanced age was like! Also it gave us more time to save up and make sure we had some money for fees etc. and got the mortgage down as far as possible.
It sounds like there's a few possibilities without having to move, which is good. Your DW will probably need extra help and support around exam times. Its so competitive that if you need to be somewhere specific its worth really looking into what each Uni prefers. There are some websites - This one for instance. They are populated more by younger students, but are another source of info. The 5 yr course would prob be easier going, but you don't get the NHS bursary, so you have to pay the £3000 fees yourself, and have less grant.
Financially there are extras which help - 25% off council tax, student bus pass/rail fare, student discounts on other things, eligible for good loans.
You said you'd need about £20000 to cope. I think this year we had about £26000 on my mat pay, a bit of my earnings, grants and DP's part time wage, including student loans. And this was the toughest year as I've had 6 mths on no pay. Next year I'll prob be earning all year so have more money, but grants may be a bit less. Grants etc. are dependent on my wages, so if I earn over a certain amount we get less bursary, so if your wife is on a low wage, you'll be probably eligible for more grant.
Good luck with it all, I hope it works out - it seems to be an amazing job.