Hello, Neil. I got a 2010 vellfire a few weeks ago, with the 18 speaker system and factory roof monitor, no 360 cameras.
This Tesla style unit was plug and play, made by navirider, from Ali Express
It came with a hdmi out socket. The retailer provided a small black box, that converted the digital hdmi to 2 analogue RCA's. I then connected a standard single RCA lead from this box upto the roof monitor. Retailer also provided a breakout lead, which plugged into the roof monitor, and the original connector then went into the other side of the lead. It had an RCA cable coming off it. I plugged my RCA extension into it and it all worked, initially mirrored the display, but with help from the retailer and his engineer on WhatsApp, found out there was a hdmi assistant built in. With this enabled, you can have a video coming out the back, whisky your satnav or whatever is showing up front
It was completely plug and play. Only one fly in the ointment: the rear camera won't work. I have another on its way. But, steering wheel controls work. Also, there is some canbus interface : a display pops up with which door/boot has opened, in reverse, despite the current blank picture (!) the parking sensors show up with proximity lines, and the steering guide lines are dynamic, so once I get a camera in, I won't have lost anything. I intend to do this with a wireless transmitter/receiver kit, as I did on my estima.
There are a few small issues : you can only drop the rear monitor with the remote. It's buttons are very limited, obvious, so volume, next/previous video, is about it. One of them goes from normal to wide 1, followed by wide 2. This button finally got the display on the monitor full screen.