Hi Neil,
I see the problem. Whats happening is that FCKeditor by default is putting <p> </p> into the Summary field.
I will try to get a fix for this out very soon. In the meantime there is a hacky way it can be fixed right now.
If you edit with a text editor the file /Events/Controls/ListView.ascx
Replace this:
<div class="description">
<%# Eval("Excerpt") %>
</div>
with this:
<div class="description" runat="server" Visible='<%# (Eval("Excerpt").ToString().Length > 13) %>'>
<%# Eval("Excerpt") %>
</div>
Best,
Joe