And to include Swanley?. Both stations are within the M25 area and are
included in the Freedom Pass area (and quite sensibly too...)

Dartford in particular is an important interchange for the three lines to
the west through Bexley.

When I asked Bexley and Dartford councils ages ago, their view that it's
"nothing to do with us, contact TfL". Similarly Connex were not interested
and directed me to TfL. After a very lengthy period, TfL replied and said
they completely agree that Dartford is an important interchange station for
lines serving Bexley, but it was strictly outside the "Greater London" area
and it "wouldn't be appropriate" to use GLA funds to pay for an expansion of
Zone 6 by compensating Connex for any loss of revenue.

Are there any precedents for stations outside the Greater London boundary
being in the Travelcard area?

Nick