Teams Whiteboard not Visible to Channel Members

Hello

I have a Teams Group with approx 30 members.

Within the group, I have three channels which each have approx 10 of the 30 members.

I have created a number of Whiteboards within one of the channels for those 10 people to complete and add to at a time that suits them.

When I created the whiteboards I did not select to 'Post to the channel about this tab' before hitting save. I did so to avoid a Facebook style 'status update' notifying all channel members of the board, before it was ready.

However, the whiteboards are now created, but none of the channel members can see them.

Where they should be along the top, all they can see is 'Post' and 'Files'.

Even if I go to my Whiteboards in OneDrive and give access to all group members, they still can't see the whiteboards.

How do I give the channel members access to these whiteboards that I have already created and that are currently only visible to myself and other Group Owners?

Thank you,