On 25 Oct, 18:35, John B wrote:
If you want to travel home on fast trains during the peak, then you
can buy an annual Network Railcard for £20 (at any rail ticket office)
which gets you a 1/3 discount on another Standard Day Single from
London to Didcot, i.e. £13.55, for a total of £34.50.

BUT railcards are not permitted on fast HST or Adelante services from
Paddington in the evening peak, You have to pay full fare to travel on
these services.

You can however, use a Network card discount on the slower turbo
services.