Found the media unit after removing the glovebox.
Hangs from a bracket, unfortunately cables behind it are too short for it to slide out fully so you need to drop down the bracket. Screws are behind the centre dash trim piece.
Looks like a standard ISO multiplug which you can just pull out the speaker section and then the usual amp business from there once I get the cables.
I've attached some photos if anyone wants to see this for future reference