Given the cash EI have in the bank, the LHR slots, the assets (they normally own roughly 50% of their fleet right?) and the fact they are a profitable business, I think this was deliberate undervaluation by IAG, they put in a bid they knew would get rejected to put a shot across someone's bow. Either giving the shareholders a heads up that they're interested, or warning a rival that IAG may start a bidding war and make things very expensive.
I don't think the unmentionable will be looking at getting 49% of EI just yet, they are bound to be up to their necks in s*** with AZ now