What price a preposition?

The headline to this article made me aware of a pretty big ambiguity in its contents: there's a big difference between saying that "in 30 seats UKIP are likely to win", and "UKIP are likely to win 30 seats". 

To see this, consider the statement: "Chelsea are likely to win every game they play this season".  Interpreted one way, you're just saying that Chelsea are favourites in each game they play (plausible).  Another meaning would be that Chelsea are likely to win all the games they play, which is exceptionally unlikely (no-one has ever come close).

Of course the results in different seats in general elections are strongly correlated, much more so than football matches.  But I'd still like to know what exactly the Guardian means.