Head unit wiring

[Zagidave]

Hi all
In the process of converting my lwb custom into campervan/ day van.
And trying to add some speakers in the rear.

Has anyone got the pin out details for the radio head unit or link to wiring diagram?
I have searched on here and found info about wiring to rear panels,
but I have already insulated and sealed these so prefer to run new wiring.

Thanks Dave