By calculating how many times the patio doors were used to enter/exit 5A you're inferring that you accept as a fact that they were so used.
Why might people say the patio doors were unlocked Monday-Thursday evening if they weren't? Obviously I don't know, but hypothetically to hide the fact that they were only left open on 3rd.
You may agree with Mrs Fenn that the patio doors were heard sliding on Tuesday because the parents were returning, but as neither of you saw them it's still an assumption. The fact is that she heard the patio doors, not that it was the parents moving them.
But to make progress you have to use reasonable and sensible inferences.
You say you obviously don't know why they would say they used these doors it they didn't and that's just it there's no reasonable explanation to explain why they would say this if it wasn't true. Even if one takes the position they were directly involved in MM's death how does having the patio doors unlocked assist?
Agree Mrs Fenn did not see the McCanns arrive but I think its reasonable to draw a sensible inference:
- Mrs Fenn hears what she thinks is MM crying and calling Daddy, Daddy which gets louder and more expressive
- This noise goes on from 10.30 pm to 11.45 pm
- At 11.45 pm Mrs Fenn hears the patio doors open and the noise stops
If the above wasn't the McCanns entering 5A having just left tapas who was it and what caused the crying and calling Daddy to stop?