Graham The forum twig file has been updated to improve the handling of attachments when editing a post
Basically you will now see the current attachments listed and you can delete unwanted attachments
Also the breadcrumbs tail now actually says "Edit post"
in the standard xtforum.twig file the changes are at line 240 - 248 the new code is

{% if not user_silenced %} {% if reply_to %} {% set post = thread.posts|first %} {% import _self as script %} {{block('post_view')}} {% elseif edit_post %} {% set post = thread.posts|first %} {% endif %}

the twig file at http://syntax.xtgem.com/_xtgem_templates/xtforum.twig.js has been updated to reflect the change