I suspect it depends on the T's & C's - some charge a terms fees if you don't give a terms notice of not going - so don't let them know by the Easter Hols.
ETA - just found this on website
Quote:
If you wish to withdraw your acceptance of a place after submitting the Acceptance Form and paying the
deposit but before your son starts at the School you shall give written notice to that effect prior to the
first day of the term immediately preceding the term in which your son was due to start. For boys
intending to join the School at the beginning of the Autumn term, written notice must be given to the
School by 1 May.
If such notice is received by the School by that time the deposit will be forfeited in accordance with
clause 1(b) but no further fees will be payable.
If such notice is received on or after that date, a term's fees shall be payable and shall become due and
owing to the School as a debt. Where applicable, such fees shall be reduced to take account of any
scholarship awarded to you.