At some point I imported photos in to Lightroom without allowing for them to be categorised in to date subfolders. I now have a batch of files 'loose' in my 2018 folder. Since importing them I have done a lot of editing and would not want to loose that work.
How can I organise these so that they are in date organised folders?
You can move the photos outside of LR eg. with exiftool and a command line like
exiftool -d %Y-%m-%d "-directory<datetimeoriginal" *.arw
into date folders. Afterwards, let LR know about the new locations by right-clicking the root folder in LR and synchronize.