Change Activity Title for Single Item

I've managed to change Activity to Interchange on all areas of the site, with this one exception:
http://www.mutlikeme.com/members/dawn/activity/267/
I cannot seem to find the answer anywhere, and so I have come here.
The other areas were simple to change in my child theme functions.php file.
Any assistance with this one is greatly appreciated!
Thanks, Andrea

Hi,

Maybe it will be easier to create language file with own/changed titles/labels etc.
http://codex.buddypress.org/getting-sta ... -and-urls/