I think I know the answer to this one, but would appreciate
clarification from anyone who *actually* knows...

If you have a registered Oyster card with no period Travelcard loaded
but with a positive PAYG balance, make a PAYG journey, and /later in
the same day/ buy a period Travelcard on that Oyster card, starting
that day, and covering the zones included in your initial PAYG
journey, will the PAYG journey be refunded?

--
John Band
john at johnband dot org
www.johnband.org