I think Jessamy may be deceived by the lie of the land and perhaps a spur of the forest at its top edge (Barbara Strachey shows a bulge in the wood line and I will take the liberty of thinking maybe 80 years earlier it was greater...) or maybe her fears are realised and the old forest isn't such a fixed entity!
Jessamy has managed to land herself in my consciousness so clearly, dragging her family and backstory that I will have to write her story regardless.. at the moment I "know" more about what will happen when her family realise she isn't where she is supposed to be than about herself but I am getting a few ideas now between wolves and wights and wandering woods...