JB wrote

Can you transfer the travelcard element of an annual National Rail
season tickets that has an origin of somewhere outside London, for
example Cambridge to Zones R1256, onto an Oyster card, and if so how?

Apparently you can't buy it on Oyster or transfer it.

Paul Corfield kindly checked and posted in June '07

There has been no change to the range of Travelcards and out
county sections sold from LU offices. Therefore a ticket to Hertford
East can be sold from Euston. However, and this was news to me, it
would be sold not on Oyster but on magnetic stock with a photocard
which LU offices have retained solely for this purpose.

Attempts have been made to reach an agreement to retail Oyster for Z16
plus a magnetic extension ticket from the boundary to the NR station
requested but no agreement has so far been reached. Whether this will
eventually become reality I can't say but it would give you what you
would like. ==


--
Mike D