All you have to do is toggle hotspot off then back on on your iPhone. I have never had a problem with hotspot that couldn't be fixed without just a simple toggle.
Thanks Mr Mirollin for the helpful advice. Apple’s hotspot has always been difficult but it just seems far harder to connect with the latest version of iOS. The hotspot toggle generally failed when the hotspot failed to appear in the wifi list. As I said, a network reset was necessary to make it reappear, but disconnect and another network reset would be necessary. I have since logged out and back in on both devices and the hotspot appears again, so it would appear to be iCloud related.
I just wish Apple would get it together with the hotspot. A device won’t automatically connect to an Apple hotspot so consumers don’t get their mobile data wasted, but it will connect automatically to download an iOS update and we all know big they can be. If iOS Wifi performance was as bad as the hotspot, there would an outrage. As I said, the hotspot is my main source of internet.
Given that this appears to be an isolated event, I am thinking maybe I should reinstall the os.