As much as I hate having to say this, needs must:
To secure your wedding date a non refundable booking fee of 25% of the total needs to be paid. This is deducted from the final balance.
As choosing your photographer is a massive choice, I do hold your date for 7 days after your consultation/upon receiving your booking form to give you a chance to talk it over etc.
After 7 days, if the booking fee hasn't been paid, the date will be made available to others.