Barlow did not say he saw the window lock from the outside - read his testimony and the 2002 appeal before you make rash statements.
I will make this simple for you because you are obviously confused - we will talk about primary sources - that is the original source . A book is only a source if it reveals something new - not repeats something that is in a primary source document such as a statement. So 10 people saying Anne said the window could be locked from the outside is not 10 sources. You reading a book and then saying your thread is a source is not a primary source . Get it now?
Now we are clear you will not make the same mistake again ? will you?
Well Barlow testified the window closed/locked if banged from outside.
A lot of Wilkes's book is who said what in court. If he is making everything up then he was risking a lot of lawsuits.
Interestingly I believe it was Barlow also testified that Jeremy said Sheila had committed child abuse on the twins, which Bamber had not reported. This was a few minutes after the bodies were found. I am not sure if this was before he said he didn't want Crispy messing up his stereo equipment.