iPhone SE (2020) Bluetooth to Kenwood HU query

[Paul S4]

I have a Kenwood KDC BT33U head unit that I recently fitted to my E46 BMW.
It works fine with all the other sources ( CD, MP3 Sony Walkman via Aux in. ) .....But when i connect my phone ( iPhone SE (2020) via BluEtooth, the rear car speakers are not working, only the front ones.
The sound is very clear etc etc, but I recently upgraded the shelf rears with JBLs, and when I connect my iPhone I cannot hear them...! The fade control just goes silent when I go from standard to full rear. the fronts are fine, stereo effect all works/balance fine.

I was just wondering if there is some phone setting that I need to alter to get all four speakers working?

My instinct is that the issue is more likely to be the head unit...
I have the correct adaptor cabling to convert the OEM BMW car plug to the Kenwood.
As mentioned, everything else works very well, but just not the rear speakers with my iPhone/iTunes.

Any advice welcome !

[toohuge]

https://www.ifixit.com/Answers/View/477752/Why+no+...

Seems there may be a setting in the head unit that needs changing- a few people on Google have this issue with kenwood head units

[Paul S4]

Thanks for the link, I shall follow it up.