On Apr 22, 1:49*am, "John @ home" wrote:
If it's not documented anywhere, then my opinion is the opposite. In
the absence of a documented restriction, the passenger can choose
which station to travel to within a group by a permitted route, and
doubling back is often specifically allowed

But that only applies when the station group is in the middle of a
journey.
"This extended availability is for interchange purposes only and does
not apply where the origin or destination stations are part of a
group."

So it can never apply to tickets to/from London Terminals.

The relevant verbiage is in the conditions of carriage:

"You may travel between the stations shown on the ticket you hold in
[...] trains which take the shortest route which can be used by
scheduled passenger services"

I can't interpret that as allowing anything other than the nearest
London Terminal.

The fares manual says:

"Fares for travel to and from London Terminals are shown in Section B
and are valid at the following London Stations subject to the route of
the rail journey being undertaken,"

Which is a fairly explicit declaration that only a subset of terminals
is available, and dependent on where you start from.

U