Update: Faites Simple or A visit to the train station

In the face of trainline's incompetence and just to see what would happen and anyway I was passing, I headed off to Abergavenny station and in the space of 3 minutes bought two tickets (singles are cheaper) to London and back for next week for a bit less than I expected with no hidden costs for collection from the station or a debit card or spurious insurance or whatever. There was I thinking that the best deals were only available on the web but I was wrong. And yes I did use the rejected card which of course worked perfectly. So there!