A deposit can be asked before the desk stamps a booking. Reservations made well ahead, the long formats, duos, travel, a guest's first booking and busy dates are the usual cases, though the desk may ask for any booking at all. How much, and by what route, is printed in the thread before you confirm and nowhere on this page. The deposit is the first slice of the figure, not an addition to it; what remains is settled when the booking starts.
A confirmed booking is final, and cancelling it is charged. For an hour, two or three, the notice decides the line: with over 48 hours still to run, the deposit stays with the desk as a 12-month credit towards any companion on the roster; from 48 down to 24 hours, half the agreed figure; with under 24 hours left, or a no-show, the whole figure. Dinner dates, overnights, duos, couples, extended, travel and events count in days instead: over 7 days out, the credit; 7 days down to 72 hours, half; inside 72 hours, or a no-show, the whole figure. The deposit covers the charge first and is never paid back; whatever remains above it is invoiced. The terms print the full rule, a worked example included.