"Ken" wrote

But Oyster PAYG will be accepted from Day One, throughout the
"Overground" network, even to Watford Jct., which is a big change.

Presumably Oyster PAYG will also be accepted on Southern between Watford
Junction and Clapham Junction, and on West Midlands (ex-Silverlink County)
between Watford Junction and Euston. But is this spelt out anywhere?
Presumably, though, not on VWC between Watford Junction and Euston, in view
of the take up/set down status of stops at Watford Junction.

Peter

Peter