SWT's 2010 fares announcement, including details of changes brought about by
Oyster PAYG...

http://www.southwesttrains.co.uk/Che...h-West-Trains\
-passengers-from-January-2010.aspx

Includes:

"As part of the introduction of Oyster Pay As You Go (PAYG) onto National
Rail,
there will be a number of changes to fares within London, including:
Cheaper peak time journeys
Many fares frozen at 2009 levels, including travelcards, season tickets as
well
as standard class single and day return tickets.
Off peak return tickets withdrawn and replaced by Oyster PAYG off-peak fares
Change to the times when off peak fares are available in the London area"

Which all seems to match what has been gleaned so far from other sources.

Unfortunately it seems there are also to be new afternoon Super Off Peak
restrictions:

"In line with the Oyster PAYG off-peak fares, there will be a change to the
times when South West Trains' Super Off Peak `turn up and go' ticket is
valid
for journeys from London"

Paul S