Iphone 5 + sony mw600 bluetooth headset

Hi people im in a bit of a dilema..

Ive got an iphone 5(6.1.4) and i use a sony mw600 bluetooth headset..

When i play videos on my iphone there is a 1second delay from video +audio ie when the persons mouth moves to talk on the video a delay of 1 sec to i hear the audio,which kinda ruins watching videos or youtube etc..

So i thought my mw600 whas bust so i ordered a new one off amazon£30 to rectify the problem..and guess what it never,the new headset has also got this mystery 1 second video to audio delay..

Any one wlse experienced this..

Hmm and thanks for reading..

Is iphone 5 compatible with the sony wm600 as ive got 2 and both have a delay bug..