I have only recently passed my PPL, hence the reply to this long forgotten thread.
I have been reading up on the rules regarding the recording of flight time, according to the rather cryptically named
Part-FCL / AMC / GM from the EASA regulations, section "AMC1 FCL.050 Recording of flight time" explains that "the applicant for or the holder of a pilot licence may log as PIC time all solo flight time, flight time as SPIC and flight time under supervision provided that such SPIC time and flight time under supervision are countersigned by the instructor" (b) (1) (ii)
It goes on to say "PICUS flight time: provided that the method of supervision is acceptable to the competent authority, a co-pilot may log as PIC flight time flown as PICUS when all the duties and functions of PIC on that flight were carried out in such a way that the intervention of the PIC in the interest of safety was not required." (b) (5)
I read this to mean that on a checkout flight, as long as the instructor does not need to intervene for safety reasons and he countersigns the remarks column, you can log the time as PICUS (or P.1/S) and it counts towards your PIC time.