Hello i have the sony mdr1000x bluetooth headphones and i have been using them just by the bluetooth settings on my iphone 6s running the latest version of ios11 and i wanted to connect the headphones to the app so i could change the settings and have a mess around with them to suit my style of listening, i downloaded the app of the sony website, i turned the headphones on and tried connecting them through 'connect to the paired headphone'  on the app and it came up with an accessory pop up that said 'select an accessory' so i waited for it to pop up but it didnt pop up, bearing in mind there is another option to 'connect to the new headphone'. so if anyone can help me find a way to connect the headphones to my phone app it will be much appreciated.

Many thanks

Max