If you want clarity about the requirement for buildings to have, in the first place, single sex toilets, with 'universal' toilets as an optional extra, or as an alternative if there is insufficient space for segregated toilets, you [and arguably the GLP] need to read a bit more widely - workplace rules, equality legislation, health and safety directives, building regs etc.
Doing a textual analysis of the EHRC's wording is not the ideal way to get the clarity you seek about toilet provision, it's always best to go back to the primary sources.
Would it be helpful if I posted again that link I posted for you a while ago to the HM Government Requirement T1: Toilet accommodation document?