11. A contract for the acquisition from a housing authority of an estate in an approved site or premises erected thereon may be subject to such conditions as the housing authority, with the approval of the Department, may determine including, but without prejudice to the generality of the foregoing words, a condition that the contract shall be voidable at the option of the person acquiring the estate if he does not for any reason, or within any period specified in the contract, obtain the grant of a licence for premises on the site or, as the case may be, for those premises.N.I.