So I think the confusion is caused by Twitter and Ticker modules in Xibo.
Since you’re using RSS feed then you’re actually using Ticker module to display twitter feed as a rss feed.
I didn’t test it, I’m not sure what output this site is giving - perhaps some tags might be different than the default ones.
So you can keep experimenting with that or use actual twitter module integrated with Xibo - http://xibo.org.uk/manual-tempel/en/media_module_twitter.html
Then in the search term you’d just put from:<accountname> for example from:BBC
Have a look here on how to create more complex search terms and then put them in Xibo twitter module.
Advanced Twitter Feed