Hertsman wrote:
Here is the information you need:

Gold Card holders can also buy a Network Railcard for another adult
for just £1. The Network Railcard Partner Card gives 1/3 off leisure
travel in the Network Railcard Area. Find out more about the Network
Railcard. Only one £1 Network Railcard Partner Card can be issued
during the validity of the Annual Gold Card.

also anything you want to know about Gold Cards he
http://www.nationalrail.co.uk/times_.../goldcard.html


AIUI you cannot put a network railcard on to a PAYG oyster to get a
discount. It's only gold cards that are eligible for the discount.

(Not completely unreasonable, network railcard discounts have a
minimum fare which would exceed any PAYG oyster fare)

Tim.