I've just realised what a stupid mistake I made in my post: I am sorry for quoting the price in 'pounds'....I forget that not everybody lives in England!!
This equates to 159 euros.
Let me just add two things:
1) I myself have just booked a flight with Swiss, LHR-ZRH-EZE for a really good price..320 pounds.....in Business class!
2) Have a great stay in SFO!