It depends on where the session will take place, you will have to pay for the session in advance.
Bounds Green and Highams Park (on Tuesdays) don’t require payment in advance but all the other clinics they do.
The same for Skype sessions
Prices are as follows:
Voucher sessions £150 for 3 sessions
Phobias – £250 voucher for 4 sessions
Skype session – £50.00