In message om,
Grendel writes
[...]

On another note, a driver on the 419 route from Hammersmith to Richmond
yesterday tried to tell me that all Travelcards were not valid for all
bus travel in London, regardless of their zones. I pointed out he was
completely wrong, and he let me travel after a small amount of polite
argument. But still.. I shouldn't have to endure this kind of hassle
every time I want to get home.

You are quite right, you shouldn't!
Travel-cards for any zone combination have been valid on all bus routes
(with a few exceptions) since summer 2002 IIRC
--
Kat Me, Ambivalent? Well, yes and no.