Where did you hear this, it is news to me and I have several connnections in WCC. At the present we have a job filling up the pax a/c with cargo as the rates are not only competitive but almost suicidal.
BA do work with Atlas using 2 747-400F but I cannot see that they would be hiring in DHL to do 757 work. Bear in mind much of the inter - europe that a 757 would do is now road freight or trainned to the destination. I will ask around.