You might find it easier to extract the correct link from the descriptions in the RSS feed. To do that implement the get_article_url function in your recipe.
Something like
from calibre import browser
Code:
def get_article_url(self, article):
original_url = BasicNewsRecipe.get_article_url(self, article)
raw = browser().open_novisit(original_url).read()
soup = BeautifulSoup(raw)
# Find the link to the actual article in the soup and return that