On Mon, 31 Oct 2005 15:02:56 -0000, "TKD" wrote:

I live in south London, and can't use Oyster for my season ticket to
Croydon, because it's not valid on trains.

You are misinformed. Any season ticket sold on Oyster Card can be
used on the NR trains for all the zones it is valid.

Perhaps a slight clarification is needed he Croydon to London
Terminals season tickets are not available on Oyster. Zones 1-5
Travelcard seasons, however, are.