Hmm, bit easier in the States. You can only log time as a student if you are dual with a qualified instructor,or solo under direct supervision. That's as I understand it anyway.
If that weren't the case, I'd have been able to log my glider intro flight which was an hour of dual with a commercial rated glider pilot (also ATPL etc). But as he was not Glider CFI qualified, I couldn't log the time.