Ok managed to make the game work. I deleted the game and re-install it on my ipad (you do not lose your data/story characters/quest, they are saved via PlayFab - Thank you Ripe for the info).
After re-install:
Purchases ok - Treasures ok - Gold ok.
Had only 18 out of 22 story characters.
Lost progression in story mode (finished AD3 on legendary, but after re-install only Brigandoom was available)
Started deleting some of my mule characters and the 4 that I lost reappeared.
Created a 2nd save file and my story progression in normal difficulty reappeared.
Happy that I can play the game