There are also PACE rules about how the Police should deal with children. If men are allowed to search women, even if they "look like women" (according to Nicola1978x) then male officers taking advantage of this could also be guilty of child sexual abuse or of enabling child sexual abuse:
Scenario 1: Where a child (0-13) or young person (14-18) is incorrectly treated as an adult
"There are specific rules and responsibilities to observe when detaining a child or young person. Where no record of a person’s age is available on arrival in custody, for example if they refuse to provide this information or if they have no means of proving age, officers need to make a decision about whether they should treat the individual as a child/young person or as an adult."
Scenario 2: Where a child or young person's age is known:
Intimate and strip searches of children and young persons
Intimate search (physical examination of a person’s body orifices other than the mouth)
An intimate search of a child or young person may take place only in the presence of an appropriate adult of the same sex, unless the child/young person expressly asks for an appropriate adult of the opposite sex, who is readily available. The search may take place in the absence of the appropriate adult if the juvenile specifically requests this, provided the appropriate adult is present when the request is made and the adult agrees. The decision should be recorded and signed by the appropriate adult.
www.college.police.uk/app/detention-and-custody/detainee-care/children-and-young-persons