20. A police officer may enter a brothel or escort agency where the officer believes on reasonable grounds that—
(a) an offence against section 11, 12 or 14 of this Act has been, is being or is likely to be committed on the premises; and
(b) it is necessary to enter the premises for the purpose of preventing the commission or repetition of such an offence, investigating such an offence or apprehending an offender.