Does UniversalAndrRoot not work for it? http://www.androidtablets.net/forum/android-tablet-hacking/545-easy-one-click-root-android.html
head over to XDA and check out KINGROOT - xda-developers DevDB or check this thread out : Stock 6.0/Marshmallow firmware for UK/GB XT1072 (fast download) you will probably have to join but they are a great bunch of people.good luck