Add comments to Webform Submission pages We use webforms for a variety of purposes such as feedback questionnaires, contact forms and request forms.

For the request forms we would like to attach comments on the submission page. This is so after the form has been submitted the User and admins can communicate on the follow up from the Request.

From what I understand the submissions pages are unique and only viewable to users who submitted them OR admins.

Anyone have any idea how I could attach unique comment forms to these submissions individually so that only the User who submitted the form and the admins can comment? Would this require a module or is this something which can be a theme override in template.php?
You would need to create a module for this. It doesn't need to be complex though. But you need a place to store the comments and some code to add the form and handle form submissions.

If you wanted to make something a little bit fancy, you could notify users when new comment on submissions are made.