Yes, be very very careful! I did as everyone advised me NOT to, and paid up front.
However, I paid at the start of a full-time PPL course so my money was only in their bank for a maximum of 8 weeks. So, what were the chances of the company going bust in 8 weeks? That's what I had to assess.
Firstly, they were/are a Limited Company so I obtained their Statutory Reports from Companies House and a full Dun & Bradstreet credit report. As an accountant I have easy access to these but they are obtainable over the internet for a fee.
Healthy finances, long standing operator of known repute, max exposure 8 weeks! I reckoned it was OK (and it was!) and I would do it again but only with this company.
However, I am not sure about an Aero Club. Is the above information freely available? Would they show you their accounts? How are they funded? Limited share capital by guarantee? Or just Members' subs? Do they offer any security on monies paid in advance? How long do you anticipate your PPL to take i.e. how long will they be holding your money?
These are just a few things you need to consider as well as the saving made versus interest lost!
Cheers
Whirls