Hello richard hellyer,

Please find the answers to your queries below.
We want to be able to 'publish' a blog entry with an 'unpublished' status (see attached screenshot)
-- we are hoping that notifications to subscribers won't be sent at that time .. is that true?

Yes, you can configure from your backend > Easyblog > setting > Workflow > general > Default option > Default publish status ( http://screencast.com/t/EatRb5Oxc )
and that notification is won't sent out when you select "unpublished" status.

When we change the status of the blog entry to 'published' , will notifications to subscribers be sent out then?

Yes, if that blog post is never published before, then it will set the notification to your subscribers.

and a final question along these lines. We have some blog posts that were created before we enabled notifications. Is it possible to trigger notifications for those older posts? (perhaps by unpublishing and republishing them ?)

I'm sorry that i misunderstand on this question just now, actually you can trigger the notification from your backend, see my screenshot : http://screencast.com/t/Bffwwfl5

-> EDITED