Join Date: Aug 2011
Location: Barcelona, London, on a plane
Programs: IB+ Gold, TK E+, Hyatt Globalist, Marriott LTP, IHG Diamond
Posts: 14,181
You can only upgrade with Avios from Y, B, H. Very expensive Economy fares... (and you must find award space which is also difficult on the LAX flights)
Bid for upgrade is cash only.
Not sure about US Amex but I understand it's usually pretty quick, although not instantaneous.