I found a useful answer on here about setting the WiFi connection order in Windows 10. Essentially you use this command:
netsh wlan set profileorder name="connectionname" interface="Wi-Fi" priority=1
But is there a way to verify that the command has taken effect? I still find that my wireless switches to a non-preferred network occasionally, even though I set the right one to priority 1 and the wrong one to priority 10.
EDIT: Or alternatively, is there a way to check why it sometimes changes network, like a log of some kind?
EDIT 2 - Thanks Moab for your comment - the Event log in that link is very useful. But I'd still like to know about checking the network priority if possible!
Event Viewer/Applications and Services logs/Microsoft/Windows/WLAN-Autoconfig