Yes they have done a deal that in the event that FR buy EI that they will buy the slots. That is spotting an opportunity if it comes along, it is NOT circling around the slots. Quite frankly they would have been stupid to pass up such an offer, however equally I am sure they are well aware it may well never happen.
There is a subtle difference.
My point is that BA are interested in EI's slots and if they felt they had a realistic chance in getting them, they would hence the term "circling"
Currently however its not likely to happen, then again stranger things have happened in this industry...