If an abductor slipped in via the patio doors he/she would be mindful of noise and there would be no need for him/her to slide them right over just enough to slip in. If my suspect is correct I would describe the person as petite. This also corroborates the fingerprint evidence on the shutter where an unidentified print was found and thought to originate from a youth or woman but not not a child.
Bottom line is that it doesn't matter what PF actually heard. What's important is who she was discussing all this with and who they might have repeated to and who overheard.
Why someone would slip in via the patio doors and then handle the shutters I can't imagine.
However. The PJ recovered 5 of Kate McCann's fingerprints from the inside of the children's bedroom window. Three were from the middle finger of her left hand, the other two being from her forefinger. Then on 4th they found;
Side of the patio door: One adequate print recovered but not matched to known persons.
- Outside of one patio door: Eight inadequate prints were recovered.- Outside of [the other] patio door: One inadequate print was recovered.- Outside of the external blinds to the children's bedroom: three inadequate prints were recovered.
So the only adequate print was from the patio door, and that was identified as being from one of the GNR officers.
https://www.mccannpjfiles.co.uk/PJ/FINGERPRINTS.htm