okay, so as we all know, 29th september was a false air date and we now suspect it to be october 6th, and it is!
It's been confirmed on Wikipedia:
'Series 5 is scheduled to air on October 6th on BBC1. Once again there will be 13 new Merlin episodes in the run, and it is expected to air uninterrupted, finishing shortly before the year is out.' Follow the link here, series 5 air datescroll down to where it says 'series 5'
woohoo! it confirms our suspicions!