Good Morning! So here's the current situation for me:
Thanks for your advice @Peter. I've re-imaged one of our Intel NUCs with Windows 10 64bit build, installed the 1.8.2 client and connected it to our 1.8.0 server in our Docker test environment. Set the default layout using the aforementioned YouTube link and everything works seamlessly.
Because the latest client would not be accepted in our live environment (1.7.4 server) I kicked down the client to 1.7.9. This also works seamlessly. I've left it running since Friday afternoon (30th June) and there are no error messages, it hasn't frozen or stopped working. Great!
So the only noticeable thing to change here is upgrading our operating system to Windows 10. Now that we have a working solution, I will seek to upgrade all NUCs to Windows 10 so that if we decide to stream anything from YouTube on any device, we will not have this problem.
Thank you @executiverocker for raising this issue and thank you bobdigby for your invaluable contribution (sorry, only 2 name mentions allowed for newbies like me!).