Well I've eventually got round to start installing the wiring loom..
I removed the obvious stuff before placing it roughly in position in the car. I then set about removing some of the wires from the steering switches and fuse boxes etc.. which seemed easier to visualize what goes where when it's in the car rather than on the floor..
I've fabricated a shelf under the scuttle to install all the relays, wiring, immobiliser and ecu, to this shelf I can securely fix brackets to hold the various components in place.
Here is a picture of the wiring roughly laid out in place. In the background you can see the ecu already mounted in place.
I've also fabricated a cover to go from the shelf to the underside of the dash which is removable. This will keep the electrics unaccessable to the interior of the car when the cover is bolted in place (you can just see it holding the dash in place without the scuttle).
I've got other things on the go but don't want to give too much away yet.