Good question, I don't know. Some suggestions:
I tried setting up the Turn Up The Volume! movement and we held two sucessful national workshops. This, I believe, helped bring together the main themes, involve patients (who are often not involved in these type of forums) and link people together who would not have met otherwise. The workshops were attended by senior NHS people, and then shunned by the NHS. http://www.carerightnow.co.uk/turn-up-the-volume-resources-2/
I have been commissioned to conduct a few workshops on whistleblowing (looking at the situation for all angles and encouraging reflection) in NHS trusts, and once in a University. They were well received locally.
The NHS Whsitleblowing Support Scheme commissioned a study by Liverpool John Moores University in 2019 'Final evaluation survey - NHS whistleblowers support scheme' I have asked several times when this is to be published but received no reply. This may shed some light on the situation. Realted NHS web page: https://improvement.nhs.uk/resources/whistleblowers-support-scheme/
It's a tough one to crack and very senior people just won't talk about the deep seated problems of victimisation and blacklisting of staff and patients, and have unlimited resources to try and keep a lid on it. As exemplified by the National Guardian's Office, which as you know I believe is a dangerously (some say deliberately) flawed initiative.