Horses led to water do not always drink. Several years ago. The Primary mathematics syllabus changed much? Category theory on there now, is it? We call it Year 7. Probably. Then why has a retired Primary teacher leading mathematics interventions for the same pupils in the same Primary for the past three years? What are their teachers doing? Category theory after all? There is not that much mathematics to cover. You've got seven years to teach pupils basic arithmetic and introduce them to a couple of other areas. You're not being asked to build Rome in a day but still Primary teachers stray into non-statutory areas. Teach the methods, the understanding follows.