Returning along the central line we have a problem to consider. My route says that the next place we go is Walthamstow Central (gateway to the Victoria Line), the problem is getting there.
There are bus services from Leyton and Leytonstone, but neither of them are frequent enough that I'd want to rely on them, which leaves train services. As you can see from the inset Walthamstow is on two mainline services.
The cyan service runs from Liverpool Street to Chingford every 15 minutes, but Liverpool Street is quite a long way out of our way.
The gold service, OTOH, runs from Barking to Gospel Oak via Leytonstone High Road, but there's a 500m walk at either end and it only runs every 30 minutes.
As the timing works out, we probably want to get the gold service if we can definitely catch it, but not wait more than about 5 minutes at Leytonstone High Road station, otherwise we want to try and get the Liverpool Street service.