Ford Focus Edge 1.6 tdci ex fleet speaker and steering wheel volume control issue

[Luke1985]

Hi, I have bought a 1.6 tdci focus edge 2014 reg estate that was some sort of fleet work vehicle previously. It has had a light on the roof that has been removed and seems to have previously had some kind of radio installed similar to one you would expect to find in a police car that has also been removed. The rear Speakers and the steering wheel volume control are not working which I am assuming may be related to the things that were previously installed and may have not been reconnected properly upon their removal. I am wondering if anyone has any info on how to reconnect them properly or get them working again.