Barry Salter wrote

They are required to offer the cheapest *available* through ticket
for
the journey being made. However, that doesn't mean that staff are
expected to know every possible set of tickets for a given journey.


As I said and you snipped "Multiple tickets can be suggested too but
are
not required know-how."

It also depends on what Ticket Issuing System that station uses.
Cubic
FasTIS, for example, will show Travelcards where appropriate, in
addition to point to point tickets, whereas other TIS will only show
the
point to point ones.

So how would a CDR+ODTC ticket be issued if it isn't shown ?

Having said that, Colin's example of Cambridge to Putney doesn't
require
rocket science to work out that a Travelcard is cheaper...

And as it is "one ticket" the spirit of the rule requires it to be
offered,
even "from their machines" as in Colin's example

--
Mike D