Hello CliveHello,
In my use of both PhD & Lr I'd never attempted to get them to "talk to each other", assuming that wouldn't be an option. That's consistent with much of the photo & video software I use, so a fair assumption.
In LrC, when you "Export as Catalog..." you create a Catalog folder containing sub-folders & the Lr Catalog file (.lrcat format). PhD does not recognise this format, just as Lr doesn't recognise PhD's project file format (.phd). I wouldn't have expected them to.
In order to "migrate" from Lr to PhD, retaining all your metadata, tags etc, it's going to be necessary to
export all the photos in your Lr catalogs, making sure you select the right options in the export dialogue.
Once that is complete you can import the photos/folders into PhD, which will recognise all metadata, keywords, face tags, etc.
Yes, just as Lr detects the folder structure on your drives so does PhD. If you have (for example) a folder structure that looks like D:\Pictures\Photos\YackPix (along with various other sub-folders) when you import the Photos folder into PhD, you'll see the same folder structure reflected.
If I've missed something, please point it out.
PIX
PIX YouTube channel