First I figured out where Audirvana is creating Folders during first installation ( done by a clean install of Win10 on a second machine ). Then I compared it to the folders Audirvana created on my Laptop. The next step was kind of trial and error…I decided to delete folders by date and name ( 1024, 1025…e.g. - if you know when the last update was done it’s quite easy, and I checked the content… ), except those are the same on both machines.
The regular deinstallation process isn’t that clean, if you deinstall, for example Ver. 1037 the folders of previous versions will remain. So I think it might be a good idea to implement a clean-up funktion in further releases. Manual deleting is kind of uncomfortable… 
My workaround might not be the easiest way but my intention was in first to find out what causes the strange sorting behaviour…another side effect ist that audirvana seems to perform a bit faster now.
Thanks for that. As you will have read, uninstall and removal of the Apps folder does the same job.
I have solved the mystery of the two mis-sorted albums. When testing with lots of albums and trying lots of experiments one should be careful to note what one is doing. I had changed the sort order of the two albums during earlier experimentation and forgotten that I had done so! 
So, in conclusion, it would seem that version 1031 works perfectly PROVIDED earlier installs are cleaned up.
Today, for reasons that don’t matter, I had to rescan all my music. The albums all went back to the wrong order!!!
I’ve now tried deleting the database and re-scanning - no good. I removed Audirvana, deleted all residual folders and content and re-installed - no good. Sorting by any other field looks OK but sorting by Album Artists give me a nonsensical sort order. I can’t even figure out what it is trying to do!
@Damien - do you have any idea what is happening?
Edit - After four rescans, the albums are now showing in correct order. Although I am fine for the moment, there is clearly an underlying issue here.