Sigh... it's looking increasingly like I'm going to have to give up on this new office chair after all, after using it in anger for a few days with an adjustable desk that I can try to work around its height-limitations with.
The problem is that it is ultimately way too low for me.
So, just as it was 3 months ago, I'm back to square one in my search for my next long-term office chair it seems.