I can think of about 10 schools myself, over a 5 year period, of which about 3 went down with all student deposits. That's 30%.
Of the 3, two were the victim of major internal fraud.
30% is not a good risk for say £5000 advance payment.
Incidentally, and I speak as someone who has been in business for 27 or so years, Dun & Bradstreet or similar checks are nearly worthless. D&B are easy to fool. The best single indicator is how long somebody has been operating under the same name and with the same person(s) at the top.