Thanks for those links Klojum. I didn't think there was anything I could do this end, but happy to help test any potential fixes.
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Update
I managed to SSH into my RPi3 and inserted the couple of lines that jakermx suggested and now the video plays, but it looks like it's upscaling a 320x200 video. Guess Ill have to wait until some people much smarter than I look at the issue.
Update 2:
Another reboot and all seems correct again. Thanks again Klojum.
As we do not have a crystal ball in our midst, log files are the next best thing.
As soon as I posted that I knew that I should have 
In my defence it was late and brain should have been in restore mode many hours before ...
Hi Team
Anyone have any ideas why the Netflix Addon may have stopped working overnight? Nothing has been changed on the RPi3 we're running, and everything was fine last night, but today we load a program, get the spinning load circle and .... nothing. Menus etc work fine, just not video or audio at all.
Only thing I can think of is the input stream.adaptive is incorrect / out of date, but it won't allow me to update through normal 'update Addon' scenario. 
I can upload logs if necessary.
TIA
