Not sending replies to post comments

Hi Guys
Anyone else had this issue.
If a visitor comments on a post, we receive the email, but when you log into wordpress admin to view the comment and approve and reply, the reply does not get emailed out even though it says it is sent.
All mail server settings are correct but the reply is not even getting to the mail server.

Many thanks

The page I need help with: [log in to see the link]