PHP Warning: Use of undefined constant VBA_SCRIPT - assumed 'VBA_SCRIPT' (this will throw an Error in a future version of PHP) in ..../includes/functions_navigation.php(802) : eval()'d code on line 1 Moved topics
Why don't you implement standard board functionaoity with your topic move, that is, when a user clicks on a moved topic, it takes them to the topic in that new location. Nothing more annoying than a dead-end link.
When you click on that link it takes you to the original post, then just click on the link in the post - "For Sale or Trade/Swap" in the text
"This topic has been moved to For Sale or Trade/Swap by Ausfish."
Rather than just send people straight to the post from the message index page, as the original post could be indexed by search engines and the redirect then gets indexed. People may have also bookmarked the original post. This way no matter which way people use to get to the post they will see the text saying it has been moved and will be able to get to the new location.