These posters have appeared at such far flung locations such as Three
Bridges and Portsmouth Harbour. Is there much point in advertising
Oyster this far away from the capital?

They're advertising at Wagn stations, including Hatfield, and of
course, you can't get an Oyster issued or accepted there!

At the same time that the posters appeared, Wagn has put a notice up on
their website;

----
"Please note that Oyster "Pre Pay" can only be used to pay for
journeys on Wagn services between Finsbury Park and Kings
Cross/Moorgate.
click link to get to...

Transport for London's Oyster Card can be used in two ways:

As a Travelcard Season Ticket valid for one or more Travelcard Zones.
This can be used for travel between any mainline station within the
Zones and Dates for which the Oyster Travelcard is valid.

Please note that the Travelcard Area comprises 6 Zones and the Boundary
of Zone 6 for Wagn is Hadley Wood and Crews Hill.

As pre-payment for any journey on London Underground, London Buses and
DLR, and for a limited number of main line rail journeys. Journeys on
Wagn that can be made using "pre-pay" are those between Finsbury
Park and Kings Cross/Moorgate and between intermediate stations on
these routes.

"Pre-pay" cannot be used to pay for journeys north of Finsbury Park
on Wagn services. Tickets for journeys on Wagn services to stations
north of Finsbury Park must be purchased before leaving Finsbury Park."
----

Now, as it happens this means two things;

1) It means there's a good chance people have been asking Wagn about
Oyster, and it may eventually mean they decide it's a good idea to
start accepting/issuing them.

2) It also tells people that a Zone 1-6 Oyster will work to Hadley Wood
or Crews Hill, so it's possible (and significantly cheaper) to get an
Oyster for that part of the journey, and a standard season for the
boundary to your chosen station, than buy a Wagn season for the whole
thing. End result; same Gold Card discounts on other travel and a much
cheaper ticket. The only loss; 8 complimentary first class tickets and
a 20% discount at mainline stations (which is irrelevant, as showing
ANY Gold Card still gets you 20% off!).

Jonathan