No, these are the Windows builds, as reported by WINVER
Desktop 1: 1909-18363.1316
Desktop 2: 2004-19041.746
Laptop: 1909-18363.1256
Both desktops can see the laptop on the network, so the network itself is working. But the laptop can't see either desktop PC.
The laptop has not been switched on for a couple of weeks so should be free of recent updates until I allow them.
Most annoying this kind of thing when all the troubleshooters claim there is no problem. It should be working but isn't. Seem to spend more time fixing these computers than getting anything done. Typical - just when I had a full day at home to get things done.