Ab initio teenager - tailwheel or tri...?

[Jim59]

EASA requires differences training for LAPL(A) per FCL.135.A and the PPL holder who has a class rating per FCL.710
(Note: differences training does not necessarily involve any flying - it could be a briefing or being told to RTFM.)

FCL.135.A LAPL(A) — Extension of privileges to another class or variant of aeroplane
(b) Before the holder of an LAPL can exercise the privileges of the licence on another variant of aeroplane than the one used for the skill test, the pilot shall undertake differences or familiarisation training. The differences training shall be entered in the pilot’s logbook or equivalent document and signed by the instructor.

FCL.710 Class and type ratings — variants
(a) In order to extend his/her privileges to another variant of aircraft within one class or type rating, the pilot shall undertake differences or familiarisation training. In the case of variants within a type rating, the differences or familiarisation training shall include the relevant elements defined in the operational suitability data established in accordance with Part-21.
(b) If the variant has not been flown within a period of 2 years following the differences raining, further differences training or a proficiency check in that variant shall be required to maintain the privileges, except for types or variants within the single-engine piston and TMG class ratings.
(c) The differences training shall be entered in the pilot’s logbook or equivalent record and signed by the instructor as appropriate.