Any LPC will count in lieu of the flight with an instructor, but you still require the 12 hours in the class if you wish to revalidate by experience FCL740A:
(b) Revalidation of single-pilot single-engine class ratings.
(1) Single-engine piston aeroplane class ratings and TMG ratings. For revalidation of singlepilot single-engine piston aeroplane class ratings or TMG class ratings the applicant shall:
(i) within the 3 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 PIC,
— 12 take-offs and 12 landings, and
— refresher training of at least 1 hour of total flight time with a flight instructor (FI) or a class rating instructor (CRI). Applicants shall be exempted from this refresher training if they have passed a class or type rating proficiency check, skill test or assessment of competence in any other class or type of aeroplane.
So if you don't have the 12 hours you need to do a Prof Check and if the rating has expired, you will also need a Certificate of Course Completion from a RF or ATO before you can take the test.