The IN relates specifically to instruction for the issue or renewal of aircraft ratings for EASA Part-FCL licences.
According to CAP 804, training for the NPPL(A) SSEA shall be conducted at an "organisation acceptable to the CAA", training for the NPPL(A) SLMG at an "approved BGA site" and there are no specific organisational requirements for the NPPL(A) Microlight. In no case is an RF mentioned and so it is logical to assume that there will be no requirement for registration in order to provide training for the NPPL(A). But then, when was anything involving CAA policy logical?