Whopity, that's not entirely true.
NPLG and BMAA recommend initial NPPL applications, but the licence administration itslef is the Authority's responsibility.
Policy proposals are made to the NPPL Policy and Steering Committee. This is an executive with representatives from all UK GA organisations - with CAA observers/mentors. Once any policy proposals have been agreed - and the CAA has given its informal agreement, everything passes to the CAA's legal department before it finally appears either as an ANO amendment or under an AIC.
A sensible process - industry agree what they want, the CAA advises whether it's do-able or needs amendment, then the legal bods do the 'shall not unless' scribbledegook and it eventually becomes law.
However, those who really want a SSEA, SLMG or Microlight Class Rating included in a non-NPPL must be careful to note that the Class Rating revalidation requirements are the same as they would be for a NPPL holder.