I purchased a Sony KD-65A1 Nov 2017 and a Sony MDR 1000x Bluetooth headphones.

sadly I get delayed Echo from my TV speakers...very annoying but the sound in my headphones is OK.

On TV I have been to ..HOME/SETTINGS/SOUND/ and selected ‘Audio to both TV speakers & other devise’ to ON. ...as suggested.!

 I cannot cure problem.  Suggestion is use a HDMI connection..

Well, having spent £3999 on Sony TV and £330 on Sony BLUETOOTH headphones

....the WHOLE reason was to avoid having to use CABLES ???

  SONY....What do you suggest.