Well folks - I think I've fecked it up and I need some help.
I got the system wires routed to the front and got access to the CAN Gateway wires and to pull the pins out and replace with parking sensor's CAN low / CAN high (Pin 6 / 16) .
Unfortunately the CAN high pin got a bit stuck on the way out of the gateway and once out, we saw the terminal was slightly bent and the terminal itself was loose (the cable was just sliding in and out of the terminal).
So we decided to solder the CAN high cable to the parking sensor's cable.
CAN low went into the new parking sensors' loom without a hitch.
Got ground connected and postive power with an inline fuse connected to the fuse box.
Started it up and saw the following:
Cruise control light on dash flickering and then eventually turning off (with no function from CC).
Indicators being eratic/sticking.
Door locking/unlocking repeatedly while driving.
Window controls inoperable for other doors from driver's side.
MFSW slow to respond.
Clicking noise happening every 3 or 5 seconds (sounds simialr to click from indicator relay - and in the same region).
Not sure what to do here - we spent a good couple of hours checking everything over to make sure it was all connected in the correct sequence.
Does anyone have any ideas on what's gone wrong? Slightly worried I may have done some damage somewhere :(
Will post a VCDS log of all of the issues that are now present.