I don't think an intruder would have entered via the patio either, for a start there were two gates.
Wow, two gates! That'll keep 'em out. The T7 had trouble working it all out, too;
we could never really work out why the shutters were up and the window was open.... if they'd come in the patio door, why would they have gone out the window, I'm sure that they could have just gone back out that way, or they could have even just gone out the front door, erm which would have been much easier.....so one of the, our theories for why the window and the shutters were open, were that you know, they came in that way and then but that would mean obviously that the window would have had to have been unlocked, you know either all week, or sometime during the day you know, thats kind of a bit of a risky thing to do because actually you know, if, if they had been checked before the children went to bed and you know Gerry and Kate had found the window unlocked, then they would have locked it and then that would have kind of scuppered anyones plans for coming in that way'.
http://www.mccannpjfiles.co.uk/PJ/RACHAEL-OLDFIELD-ROGATORY.htm