KDL-43WF663 purchased 5mths ago.  BBC iPlayer stopped working 2 days ago. 

Other services YouTube, ITV player etc continue to work OK. BBC iPlayer is working fine on iPad. 

I've tried switching off at mains, re-starting WiFi Router, re-starting TV.  Even did a Factory re-set!  But still BBC iPlayer is present but not working as before.  It lets you browse and select a program, then it buffers for several minutes before displaying a message: "Something went wrong playing this program.  If it continues, try checking your internet connection or changing the video quality in settings"

Has anyone else experienced this, and how did you fix it. 

I came across some reference to 'Internet Cache' on the WWW but what is that and does it need clearing out?