Why are only 3 visible from Membership plugin in Newsletter send list

Hi

I have imported about 100 users to the Membership plugin and assigned them to a group called CTO.

In the Newsletter plugin sent I can only see 3! Any ideas why and how I can change so I see them all?

https://www.dropbox.com/s/jv28moxv72tuf3h/Screenshot%202013-12-21%2010.51.31.png

https://www.dropbox.com/s/nappk0opg92c8ls/Screenshot%202013-12-21%2010.55.23.png

All the best
.m