My friend needed to make at least three journeys between London and
Amersham that day, so whilst I would have just bought the ticket on
offer and taken a bet, they instead opted to use Oyster PAYG and so
take the East London Line from New Cross.


I wonder if PAYG cards are still accepted at the New Cross gateline?
They should have been reprogrammed to reject them with error code 57,
but I haven't been there since the ELL closed to check this.