I am also currently non unionised having tried to send a message too.
I unfortunately went through 9 months of EG901 for "bullying and harassment" and at this time was a member of Unite.To be quite honest the union reps who came with me to the various hearings didn't have much of an idea as to the processes anyway. They are not permitted to say a lot just stop the hearing and advise you. I represented myself in the end. Thankfully the whole thing was thrown out.
Rosiegirl if you are unlucky enough to go through something like this, which is rare, you will be fine with another colleagueto accompany you.
Hopefully once they sort themselves out those who have left can consider rejoining the union - I'm not holiding my breath however!