Post Office currently has 10 people on the board, not counting the company secretary. As Tom Cooper's evidence yesterday demonstrates, it can be very difficult for one board member to change things when the other members of the board don't want to listen and have been entirely captured by the lies of the CEO, General Counsel and other senior staff. He did, of course, represent Post Office's only shareholder, but that doesn't automatically give him more authority in board meetings than other directors. And, with Tim Parker complaining that Cooper was being too interventionist and with relevant politicians apparently being uninterested, it made it difficult for Cooper to get his (entirely valid) concerns acted on. He could and should have done more, but it is clear that the culture at the Post Office was toxic (and, according to reports, remains so) with excessive secrecy and resistance to outside governance.
By the way, in checking how many directors Post Office has, I noticed that Susan Crichton was Company Secretary when she worked for the Post Office. Whilst the Secretary's attendance at board meetings is not mandatory, it makes her exclusion from a meeting in which Vennells (mis)reported the Second Sight report even more astonishing.