I have done some more testing and the problem is eliminated if I remove the html to insert an image above the info box. So the problem is caused by my insert image html? The full html in the text widget is:
<img class="alignleft" src="http://localhost/forum/wp-content/uploads/Free-Newsletter.jpg" alt="Free Newsletter" width="235" height="180" /> <p class="subinfo">Subscribe to our free newsletter and get served first whenever we publish a hot, fresh, and tasty new tidbit.</p> [si-contact-form form='2']
I tested the above html in a garden variety WP text widget and got the same issue: padding top value not recognised.
Thanks in advance for any help.