If we set the device recognition flags as follows:
The only way for an unrecognised device to have the options of both registration and login as a new device for an existing user without pressing the cancel button is to also untick the Switch Automatically to Recharge option.
Why does this option affect unregistered devices when it is only supposed to change the behaviour for recognised devices - I don't think it did on earlier versions of HSNM (we are now running 6.1.55).
Then with unrecognised devices we only see the option to register as a new user in the Login app. In order to see the "existing user" login option as well the user has to click on the Cancel button.