Hi,
the loom comes into the engine bay through the large hole in the firewall in the middle just below where the bonnet sits. The wires tot he fuel tank and rear lights go across towards the expansion tank and go through the small hole next to where the fuel lines go back in to side of the footwell and then back into the side box and run down the back running above the fuel tank.
The majority of wires come through the firewall and over to the fuse box just past the master cylinders and the rest travel along the right side of the engine bay to the right side headlight bucket and then across to the wire holder in the centre of the front panel. The connector for the headlights is here in the middle and go back to each side. The wires for the engine then travel down the grille to the next holder and across to the solenoid, coil etc.
Terry