Just checking @IAT are you experiencing the issues on a Youview box and if so have you tried any other devices ?
i also have this issue on a Toshiba Smart UHD TV bought yesterday. Is there any fix?
I did a factory reset, retaining recordings. Instructions here. Fixed it. http://bt.custhelp.com/app/answers/detail/a_id/48051/~/how-do-i-reset-my-bt-tv-box%3F