The terms P1S and PICUS are not defined in the EASA regulation for single pilot operation however; in the UK see CAP804 Section 1 Part E Page 14 para 9 Table Item J
Pilot undergoing any form of
flight test with a EASA or CAA
Authorised Examiner (other than
case K.
PICUS for
successful
Test P/UT for
unsuccessful
test (including
partial pass)
In all probability the check ride was flown with a FI not an authorised Examiner so the case above does not apply and there is no definitive answer.
Art 79 States:
(3) The information recorded in accordance with paragraph (2) must include:
(c) the capacity in which the holder acted in flight;
You are legally entitled to act as PIC and a club checkout is not a licensing test however; if flown in the 12 months prior to expiry, it it could form part of the dual flight with an instructor, in which case it would be logged as PUT.
An old chestnut that is no clearer now than 20 years ago. A little imagination is required.