A week later,
Again could not get on the wi-fi with any device all saying that a wrong password was being used. went into hub settings to find all passwords etc were still the same. Restarted the Hub by disconnecting it from power leaving it for a few minutes and then reconnecting. Devices logged in ok but soon dropped out again. They (the devices) continued to do this for the rest of the day. In the end I carried out a full reboot back to factory settings. Once the hub was up and running with new ID and passwords I logged each device in with no problems. 3 days later and problems have not come back - time will tell