The relevant text is just after your quote
4.The ratings SSEA, SLMG and TMG have the meanings given in Schedule 1 to the Air Navigation Order 2016, and the rating SEP refers to a single-engine piston aeroplane of the kind described in Annex 1, Subpart B, point FCL.105.A(a) to this Regulation.”.
If you look at FCL 105 A (a) it refers to LAPL privileges.