LDN closed my topic without rhyme nor reason
I posted what I thought was a reasonable question
http://www.lumdev.net/node/3291
No one answered me, but then Sungard gave me a small update - which I thought I would add to the thread.
There was no link to add a comment, and so I worked out what the link would be
http://www.lumdev.net/comment/reply/3291#comment-form
and drupal told me:
I thought that this was quite cruel, but also that it wasn't likely to be intentional on behalf of the community here. What did I do wrong?
Derek
University of Leeds, UK

found the solution
When you edit one of your own posts, there is a "Comments settings"
I checked the "read/write" rather than the "disabled"
Hurrah