The bathroom window is the window Jeremy used when he entered after the murders so he could certain;y open it from the outside. I think it would be possible to lock the window from the outside using a piece of cord, wrapped around the catch and pulled from the outside.
Still, one of the officers said that the bathroom window was shut but the latch was not secured. I think he used the bathroom window and not the kitchen.
According to Barlow, the bathroom window couldn't be shut from outside. This explains why AE chose the kitchen window.
So what now to make things fit?
A) He climbed out the master bedroom window via a ladder. (That's Harley's fall-back position)
B) He gives Sheila the gun after commiting four murders. Leaves via the maindoor after instructing Sheila to secure all downstairs doors and windows before shooting herself.
C) Secretly leaves a Motorola DynaTAC 8000X Mobile phone in Sheila's room. Calls her from his cottage and tells her to carry out the whole thing. And Nevills subsequent call is an added bonus alibi that does not actually exonerate him.
It seems you are spoilt for choice! Decisions decisions decisions
