Microlights are looked after in the UK by The British Microlight Aircraft Association.
The association is responsible to the Civil Aviation Authority for everything to do with microlights from approving aircraft through to pilot licencing.
Their website has a lot more information on it including the syllabus for the NPPL course and, if you become a member, you will receive monthly copies of Microlight Flyer which is easily the best aviation magazine in publication. Students get a special discount rate in their first year.