the problem now is to simplify or organise this information in some sensible way

With all respect i disagree.
The problem remains that none of these lists match and without original sources there's no way to know which is most correct.
I was surprised that u commented on this document, when i uploaded it i got an error message, looks like it worked after all!

The organisation on this page looks very similiar to the Croatian rulers project, and as this is one of the sources quoted on wiki there's likely a reason behind that!
The main differences are that our project is listing each person once and if they were Ban more than once multiple dates against them. This list is chronological so that one person can appear multiple times.
I think the chronological version is clearer but it comes unstuck with family dynasties (i just updated the Hendrik discussion), this document wrongly attributes 4 Banages (Bandages?) to one Henrik when it is in fact a fatehr and son team spread across 30 year span.

That was my doing, I have tried to shorten the list by listing multiple terms of one person so the person does not appear more than once. Obviously that makes it difficult to read.
This is not an easy job, and even if we had a 100% accurate chronolical list for all of them, who guarantees that we will be able to find where they fit on the tree.
For many of them, it takes time to build a tree up to the point where I can add them. It was easy to build list of rulers for dynasties, as they inherited their positions, but Bans were often appointed.