help please; wires and retro-fit a V70 sub-woofer

[cadaron]

Hello, long time lurking in the shadows here, but always enjoyed reading the threads.

My question is, I am in the process of buying the optional sub-woofer for my 2005 V70R, and having looked at the threads here and checking my boot space, it would appear that I do not have the pre-wired harness, and attach various photos which hopefully shed some light on what is in the boot well. I did have the optional tow hitch on the car, that I have since removed, so that may explain some of the cables.
I understand a harness was/is available which connects to the D pillar speakers etc. but before I hopefully find one of these, could anybody comment on what they see in case the pre-wired harness is hidden in the boot well somewhere.

many thanks.