well for example, an IMC test is not a test or retest for an aircraft rating, it's a personal rating.
Back to the question I was trying to raise on non-instructor checkouts and this p1/s logging. (not sure anyone has really clearly put a hand up on this one yet):
If one gets liberal and interprets Clause J as being the basis for allowing p1 and p1/s logging between 2 pilots during a checkout where no instructor is involved, then Clause J is also quite specific that if the test is failed, the failing PPL then must log as Pu/t. So would the 'liberal interpreters' want pu/t to be logged on a failed checkout flight with a non-instructor checker? Is this non-instructor checker now giving training? (despite not being allowed to do so?)
I think that gives the main clue that Clause J (and therefore p1/s) is nothing to do with rental or syndicate checkouts, as these flights could be carried out by PPL checkers.
My conclusion (make your own minds up):
Rental Checkout with instructor: If you both want the hours, cook up some reason (there will be one somehow if you try hard enough) to log it p1 and pu/t.
Rental or Syndicate checkout without instructor: one pilot logs p1, the other logs nothing. I don't care which.