i did not say that the caa WILL NOT allow you to claim the time. i said they MAY not allow you.
i asked this question as well because the examiner for my cpl told me i could log the test as p1 but did not sign it. i was worried they the caa might not accept it but still kept it as p1. it went through without a problem. if the dude checking up on my paperwork was having a bad day, maybe i would not have got away with it... who knows!
just remember when putting the flight in your logbook, the commanders name is your examiners name, but you put the time under the p1 section and have it signed.