Londoncityslicker wrote:
Dont think there is such a thing as a zone 6 travelcard.
You'd have to ask for a 5-6 Travelcard to be added to your Oyster.

Eh? The OP wants to add an extra zone of validity (by exchanging a 3-5
travelcard for a 3-6 one). It has nothing to do with adding an
additional travelcard to the Oyster or the existence or otherwise of a
zone 6 travelcard.

Anyway, the OP isn't asking if can it be done, the OP is asking who can
do it! The mistake is not going to a bone fide LUL ticket office as the
customer services suggests although I am surprised that it can't be done
online or over the phone as it is a not uncommon request. It is also
unfortunate that better advice wasn't given at the ticket offices and
that the OP had to resort to Usenet.

ESB