Section 11 of that Act (powers of entry) shall be so modified as to secure that, as from the date on which the acquiring authority have served notice to treat in respect of any right, the acquiring authority have power, exercisable in the like circumstances and subject to the like conditions, to enter for the purpose of exercising that right (which shall be deemed for this purpose to have been created on the date of service of the notice); and sections 12 (penalty for unauthorised entry) and 13 (entry on F1enforcement officer's or sheriff's warrant in the event of obstruction) shall be modified correspondingly.