Finally in effect they said The Air Ministry at Cardington shall build an airship of a certain size loadcarrying capacity and speed and Vickers Ltd shall build another one of the same contract specification

Could you correct the punctuation please?
Finally, in effect, they said, "The Air Ministry at Cardington shall build an airship of a certain size, load-carrying capacity, and speed, and Vickers, Ltd. shall build another one of the same contract specification.