handing over substantial amounts of money to
Well, you pay after each flight, don't you, so even if the school does go bust (which isn't something the CAA would know anything about anyway) your only problem is getting the adminstrators/receivers/liquidators to pass your training records to your new school. Which they may or may not be the remotest bit interested in helping you with, particularly if nobody is paying them to do it.
You have, after all, heeded the advice repeated, here and elsewhere, ad nauseam, not to pay up front, haven't you.