If you don't need a visa to go to Greece you don't need to pay an advance..
There are hundreds of people applying to the European schools only to get a visa and not follow the class.
By the Greek law to get a visa as an aviation student between other documents at the embassy will ask you also the receipt of the payment and it must be 30% of the total cost.
The solution is to say that you are going for PPL which is only 4950 euro so the advance is 1500 euro.
