In my day ... the Liverpool Education Service operated four 'streams' of schools; Grammar; Technical; Commercial and Secondary Modern. All of the schools seemed to be two-form entry. Selection occurred via the 11+ examination after which one was assigned to the different streams. [There was also a second exam at 13+ . I recall some boys joining the school I was sent to at age 11 when they were 13+ in the Third Form.] This seems to be 'multi-lateral' albeit it multi-campus .... as the educationalist would say now.