As Sussamb has closed the other thread I am opening a new one because the closure of the other thread had nothing to do with the IOS app, using Garmin Express on Windows requires me to log in to set the WiFi password settings every time I plug my watch in to my Windows 10 device, not to my IOS device.
The watch actually retains the settings, I can use GC on my phone and it connects to the watch, I can use the sync settings to update GC but I am forced to enter the password on the Windows 10 Garmin Express App.