Ok all so it seems I have solved the alternator whine noise after completing the rca mod as indicated by @
nath now before I share what I did, unfortunately I did two things at the Same time and I'm not entirely sure which one fixed the problem. So any way the first thing I did was insulate all the solder points inside the 4 added RCA's by using head shrink tube over both the positive and negate solder points on each RCA ( had this weird concept that the live wire was somehow interfering electrically with the ground as the solder point are quite close together) the next thing I did was splice the ground wire on the eonon harness (pin 15 for the GM5151) and added an extension ground (16awg) which I routed and grounded to the same point as the factory bose amplifier under the seat, using a crimp ring terminal. And that my friends is pretty much it. I have a theory the the ground in the eonon harness is pretty much shite now I have 0 hum/whine and 0 blutooth pop very clean sound I must say!
thanks so much @
nath for bringing the rca mod to our attention and letting me bounce ideas off you and providing ideas in response your a champ mate,
Edit. for anyone that doesn't know this, I also installed the eonon HD CCD reverse camera today and the red wire that comes attached with yellow video cable does NOT need to be connected on either end. In fact I cut off both ends and insulated with heat shrink.