UK X5 NAV DSP UPGRADE HELP

[3.0dsport]

Hello guys,

My X5(2004) has an 8 speaker system with sat nav BUT no DSP.
I have bought a DSP2 amp which I was hoping to install have have slightly better sound.

I found the amp plug (15 round pin) next to the spare wheel which connects fine to the amp BUT....there are 3 more plugs (18 flat pin and 26 flat pin and what looks like a remote single wire plug) which need to connect to the amp from my car.

I have searched the whole boot area thinking the plugs would be tucked away somewhere but no joy.

Is there a retro fit loom I need to get? Or am I not look hard enough..
Can anyone help in my frustration..

Thanks in advance chaps..