Are the adapters direct into wall sockets and do the lights on the adapters remain green?
Is it possible to connect the TV box directly to the router bypassing the adapters to rule these out as a possible source of the issue ?
I connected the Youview box using a direct ethernet cable. I then reset the router and Youview box. When I tried Netflix I was still having issues.
I then reverted to the Power line adaptor and reset the router and box. The Youview was initially responsive to the remote and didn't freeze but after a while the fault returned.