The wiring loom is fixed into a little plug that plugs into the eurovox. When I get a new HU is it just a matter of plugging that into the back? Or do wires have to be separated and clipped into the right parts?
You should search...
But you can buy a Aerpro loom from autobarn which will plug into the car's plugs and have wires to connect to the new head unit wires. You just match up the colours, then you can just plug both ends into the car and new head unit.