The curriculum in Northern Ireland, Scotland and Wales varies against the English one.
Northern Ireland still had the 11+ exam until recently whilst England had SATS.
I am aware of this although there is still an overlap between the two curricula so programmes suitable for both England and Northern Ireland can easily be produced.
Also bear in mind that the 'heyday' of BBC and ITV schools programmes was before the National Curriculum came into force in 1988. A sizeable proportion of BBC and ITV schools programmes produced before 1988 do not fit neatly into the National Curriculum subjects, or their equivalents in Scotland and Northern Ireland, so are just background material.
AFAIK Northern Ireland and the Republic both have very similar cirriccula compared to the England one.
There are many differences between the two. Students in Northern Ireland take GCSEs using the CCEA exam board and are not covered by Michael Gove's recent reforms.