Somthing I’ve noticed is that many of the local ticket machines (this in Croydon) provide for (Travelcard, &c, extension tickets) from Boundary Zone n to Wherever – indeed the (TfL) machines at West Croydon invite you to touch Travelcard (or Freedom pass in my case) against reader to deternine ‘n’ (6 for Freedom pass – I assume 60+ is the same). I would expect (or at least hope) that Woolwich ticket machines would do the same.