Hi Wayne,
I believe you have around 60cm of soil substrate with some leaves and growing grass in parts? That sounds fine, it doesn`t matter if the monitor mixes it all up, that`s what monitors like to do (I think deliberately, just to make a mess)...
And one last point; Savannah monitors are not unique, they do things, and need the same things as most other Varanid species, so without taking sides, it doesn`t matter if a person has kept this species or not, the advise is still relevant, if the conditions needed are very similar!