rutankrd is referring purely to the slots acquired from BA which have restrictions of use on them as already detailed.
Priory to Northern Summer 2013 VS had a number of its slots at LHR leased out to other carriers and had no domestic services of their own.
To satisfy the terms of the tendering process for the remedy slots it required that they set up a domestic operation and that those leased slots return and be used by the business -hence the Manchester services were set up and publicly launched before hand.
The presumption is whilst they have use of the remedy slots provided by BA they can not simultaneously lease out their own slots for profit.
However they have apparently be able to permanently dispose of a slot pair via sale to Delta -a clear partner legally within the letter however less so in the spirit of the contract !
The regulators might however have something say if VS dispose of further slots similarly and certainly so if they terminate the Manchester service completely during the three year period.
Nothing in this business is ever easy or transparent !