Rupert Candy wrote:

Just to add fuel to the flames, Southern have provided some clear and
unambiguous guidance (!) on this page:

http://www.southernrailway.com/ticke...s/oyster-card/

"If you already have a Travelcard but want to use your Oyster card
outside the zones covered by the Travelcard you might need to get an
Oyster Extension Permit before you travel.

'Might' is correct in that context really, because the requirement for an
OEP only applies if you are extending FROM your travelcard's zones, as far
as we can make out. As an example, if you had a season that covered only
zones 1 and 2, a touch in in zone 4 to travel to zone 6, or back to zone 1,
wouldn't need an OEP.

...If you travel with an
Oyster extension Permit you might be liable to a Penalty fare or even
prosecution."

Shocking error that bit...

Paul S