Problem. At least one ATO with privileges to instruct for the FI claims that a LAPL FI can sign a SEP rating on an EASA PPL.
Their logic being that the the holder of a PPL without CPL TK who holds an FI rating the Remarks and Restrictions on the Licence states "FCL 905.FI applies as in /(a)/(b)/For LAPL(A) only”
Then the Yellowish sheet - FCL.905.FI - Flight Instructor Privileges and conditions. Quick Reference says
(a) Instruction towards a PPL, SPL, BPL and LAPL ....,...
(b) Instruction towards class and type rating for single pilot, single engine aircraft, expect for high performance .......,
Therefore they can teach for and sign for revalidation of SEP ratings