It took me a while to figure this one out. All my computers are now Windows 10 except for a file server running Windows 2008 Server. All my Libreelec devices no longer appeared in the network and my Network receiver could no longer browse the my home network. Then one day they suddenly reappeared. After a lengthy investigation I finally discovered that my Libreelec device which I had left on for an extended period of time had become the Master Browser for the network. It appears that when a Windows 10 computer becomes the Master Browser it's only using WSD. All the SMB shares are not seen. Understanding this I made the Windows 2008 Server fileserver the Master Browser. Now everything appears in the network again.
Unfortunately I have only Windows 10 machines on the network. This HTPC would be the only exception as I happened to buy a weird motherboard which has very limited Win 10 support. After struggling with it for a few weeks I've decided to give Linux a try - and so far it works flawlessly apart from this issue with the host names.