Of course, if EASA gets its way, every SEP Class Rating holder will have to fly not just the 2-yearly training flight, but very 6 years a mandatory Proficiency Check with an Examiner....
FCL.740.A Revalidation of class and type ratings aeroplanes
(b) Revalidation of single pilot single engine class ratings.
(1) Single engine piston aeroplane class ratings and touring motor glider ratings. For revalidation of single pilot single engine piston aeroplane class ratings or touring motor glider class ratings the applicant shall:
(i) within the three months preceding the expiry date of the rating, pass a proficiency check in the relevant class in accordance with Appendix 9 to this Part with an examiner; or
(ii) within the 12 months preceding the expiry date of the rating, complete 12 hours of flight time in the relevant class, including: 6 hours as pilot-in-command ; 12 takeoffs and 12 landings; and a training flight of at least one hour with a flight instructor (FI) or a class rating instructor (CRI). Applicants shall be exempted from this flight if they have passed a proficiency check or skill test in any other class or type of aeroplane.
(2) For at least every third revalidation, the applicant shall comply with the requirements in (1)(i).
(3) When the applicant holds both a single engine piston aeroplane land class rating and a touring motor glider rating, he/she may complete the requirements of the paragraph above in either class, and achieve revalidation of both ratings.