And, as expected, that's an effective workaround - been watching Sky Sports without a glitch for half-an-hour. Obviously limits some of the channels (eg BBC) but I can live with that until they fix it. Nice one - thanks.
For others: My router doesn't identify the Sky Q box clearly - but you can find its IP with this very useful utility:
https://www.advanced-ip-scanner.com/
You also need to run as admin - just right-click on the icon for Command and select Run as Admin