Thanks for replying Peke.
I;m running Version 4.1.19.1859 on windows 10 home on a new Asus Notebook.
Here's a screen shot of a selected playlist from the media tree (no tracks in it) that I can't delete, the 'Remove' function is greyed out.

or if embedded screenshot no work here's the direct link to image -
https://photos.app.goo.gl/YT6kBFDbqrULpnn23
The same applies to playlists with tracks in them
https://photos.app.goo.gl/hfK9s2AghhKtHdpu1
I can delete selected tracks from playlists
https://photos.app.goo.gl/KAewUhJS6nc13fyf2
but as an aside, not from Autoplaylists where there are only two options - 'Delete from Library only' or 'Delete from Library and Computer'
https://photos.app.goo.gl/ux691UyeMbLWOrHx1
Any suggestions much appreciated,
S