Hi all, after implementing pretty much every suggestion in this thread, I found they were all lacking for me, the main issue being that the order numbers didn’t say in a nice linear sequence.
I.e. even though the order may have been rearranged properly, you’d end up with weird numbers, like 2/3/5/7/8 instead of 1/2/3/4/5 (e.g. @fayewatson’s https://faye-demo-app.bubbleapps.io/version-test/drag-and-drop ) or even weirder, like 2.25/2.75/3.4/4.5/5.75 (e.g. @gf_wolfer’s https://topshelf-elements.bubbleapps.io/version-test/drag-drop-list?debug_mode=true ), and those numbers just get weirder the more times you reorder.
So I’ve created a solution that, while it does use 4 actions, it doesn’t require extra hidden fields, doesn’t make used of ‘Advanced’ in the filter, only changes order numbers for records that need to be reordered, and most importantly for me, keeps the numbers in a nice, sequential order of 1/2/3/4/5.
There may still be a more efficient solution out there, but I hope this is helpful to someone 
Editor: https://bubble.io/page?type=page&name=drag-and-drop-order&id=phil-testing&tab=tabs-1
Preview: https://phil-testing.bubbleapps.io/version-test/drag-and-drop-order?debug_mode=true
Cheers,
Phil