So After quite extensive wrecking of the End and buildings all over the place the area was adisaster, so i reset it yesterday, via..
1. Open your world's level.dat, and go to Data, DimensionData, 1, DragonFight, and set DragonKilled and PreviouslyKilled to 0.

2. Del the Dim1 Folder

Started the server backup and the default dragon was there, have since killed it 3 times and no portal has been crated to goto the End Cities ..... this previously worke don 1.9.2 so im wondering if there is something ive missed or if its a bug?