"(DExEU) granted only 15 per cent of FoI requests in full"
To be fair, no government department can provide information it doesn't have. If there's one thing Leavers and Remainers should be able to agree on it's that the management of Brexit has thus far been utterly shambolic. In the three months following the triggering of Article 50 most of the requests received by DExEU would be along the lines of "What are your plans?" and "When are you going to start negotiating?" - two questions to which sending no answer would be answering in full.