Disable 'Tweet' page in Kindle conversion

I study various subjects (very mature student!) and like to keep notes on my Kindle.
It is one of my pet hates that every conversion inserts a final page inviting me to share my private notes with the world via 'Twitter', 'Facebook' et al.
Does anybody know if it is possible to obviate this annoyance?
I appreciate that this is a minor annoyance in the grand scheme of things, but if it can be avoided then why not?

TIA

David