RSS Visualizer screensaver has lost feed

I set my RSS screensaver to BBC news front page but one day it had changed to apple news for some reason. I went to change it back but BBC front page had gone from the settings list. So I called up this page: http://newsrss.bbc.co.uk/rss/newsonlineuk_edition/frontpage/rss.xml and I cant work out how to get it into the list on the screensaver settings. Some pages i've googled have said to add the page to safari bookmarks and it will automatically add it to the list but it doesn't. Others say there should be a blue icon in the safari url bar but there isn't; just an orange one. I've got the safari plugin 'saft' installed so don't know if this could be messing things up. Is there another way to get an rss url into the screensaver settings list, like a doc within the OS that i can manually paste the url into? thanks, dren.