it seems to me your still not happy with your tiler for not fitting a decoupling mat, even though he has saved you hundreds of pounds, you can't win with some customers!
im not saying i am unhappy with my tiler... im simply saying i might have preferred to lay ditra for extra peace of mind to better handle any movement or cracks that may (or may not) develop over the months/years ahead is all.
@RayTheTiler has said he would have suggested to us Ditra if it was his job so im not sure as to how you think what i said was unreasonable.
That said with all the feedback i have got from the pros to my thread has put my mind at ease and i am appreciative for the input.