Lessons Learnt           

What are the fundamental lessons that I have learnt during the build.

Work with people who know more then you, look after them, treat them with respect and pay them.
This is not a lesson that I have learnt during the build but one that I have used most of my business life.

Don't Rush
From what I have seen with kit car builders is that they rush the build and have major issues fixing installations that are built our of order or in the wrong place, so plan well ahead.

Order items that you need well ahead of when you need them.
It appears quite the norm in this business that you will be promised delivery in a couple of weeks and get far more than a couple of months.

Wiring
If there are two electrical inputs to a device, for example parking lights, where they may be switched on by a simple switch from the battery when the key is off. In addition they can be switched on once the key is on, through two different circuits.
Put a diode after each output to prevent feedback into that system. If you don't understand go to Item one.

Fuse the BMS Battery Management System.

With a wiring harness consisting of around 50 wires, if one gets nicked the whole lot can burn. Although many fuses will be inaccessible it is better than the whole lot burning.