The whole concept of re-opening of Manston as a "cargo hub" is total nonsense. Sitting as it does in the extreme southeast corner of England, south of the Thames with a river crossing at Dartford that is totally unfit for purpose, and a motorway network leading from it to said crossing being totally inadequate for the traffic it currently carries how exactly does it expect to attract cargo carriers in the number it would need to be viable. The likes of DHL, UPS and FedEx aren't likely to be champing at the bit to move there, as it's in completely the wrong place from a logistics perspective. If the integrators are taken out of the equation what exactly is left? Emirates, Turkish, Ethiopian, and Qatar that are the bread and butter for the likes of Liege, Maastricht (both well located for western European markets with excellent road connections unlike Manston) and at least two of those are already well ensconced at STN.
Sure there are a couple of 747s per week currently operating through DSA with perishables from Africa. They operate to DSA, I suspect, because the cargo is destined for the Midland and Northern fruit and veg markets (remember those in the south there are more markets than Covent Garden!!), and therefore the likes of EMA, BHX and possibly MAN will likely be the chosen refuges for these flights should DSA close to freight operations not a far flung strip of tarmac in Kent!