Sony KDL-42W653A
Software version...PKG4.101EUA
Issue started a week ago.
Youtube app version...'Youtube on TV (newer devices 2013/1012)'
Connection...BT braodband unlimited 8mb. Tv wired to router via ethernet.
Problem occurs on all videos accessed via youtube tv app.

I keep my youtube app synced with my youtube acc at all times. I have been enjoying full HD content since buying the TV before christmas with no buffering or connection issues of any kind. One week ago all videos have started playing at lowest quality (assume240p). My internet connection has been tested and is stable and more than fast enough. Netflix and other content on the TV still streams perfectly at 1080p. I can watch youtube content on both my PC and mobile phone over WIFI at full HD resolution. I also tried streaming a youtube video from my Sony mobile to the TV and this played at full HD resolution (via 'throw'). This says to me that there is a problem with the youtube TV app itself. I have restored my TV to factory settings and re-loaded the Youtube app with no change. All smart software and TV firmware is showing as up to date.

I can't think of any other fixes to try and would appreciate any help you can give. Is there an update coming out soon? I love viewing youtube on the TV and if I cant use it, the TV will be going back and I will be sad.

Many thanks in advance