Rich
Look at your comments.php and tell me what you see based on what I post here. I see no issue that I can find on this.
Lines 60-62 of comments.php are this which grabs the cat variable which your query is missing
Code:
Content visible to verified customers only.
Then at around line 166 we insert the comment into the database
Code:
Content visible to verified customers only.
Let me know if your code varies from this as all I can do is look at the code we have now. I do not have earlier versions to look at.