£20 Adult, accompanying Child £1 up to 4 per adult (no further discounts) for unlimited travel on Southeastern services (INCLUDES HS1) all day Saturday https://goo.gl/xT12p1 There is a challenge to cover the entire network in the day (see link). Available on line and at Southeastern ticket offices plus London Victoria, Denmark Hill, Peckham Rye, Nunhead, St Pancras International and Abbey Wood only.

Thanks for the heads up Paul. I’m guessing the best chance of covering most of the network in closer detail is to cover the area outside the London one day travel card boundary. Then cover the London area at your own leisure. Regards all.