Mate this is pretty simples.
Right remove the bottom end of the Glove box's ( work carefully as theres wires and the b/box is also connected to a bracket under the centre console and if you over force it it will snap
Ok Underneath the right in the n/s mid corner is a wiring loom, there's enough gap to pass a amp power wire through it is quite fidily so just be patient
Get a wire made coat hanger and wrap the wire road it and make sure you cover it in insulation tape as you dont to cause any damage underneath, the amp wire will come out by the firewall/scuttle, behind the fuse box.
Thats job done
