I have spent some time trying to understand the slot allocation regulations. From what I have found, BMI would have to be bought as a going concern for BA to be allocated the slots. If LH were to try to sell all of the slots then BMI would no longer be an operator at LHR, and would therefore have to return the slots to Airport Co-ordination Limited.
http://www.iata.org/whatwedo/passeng...s/w-slot-g.pdf
7.15 states
An airline that ceases operations at an airport must immediately return all of the slots allocated to it
Does anyone have a different understanding? If so, I stand corrected.