starter motor switch

Austin 7 electrics. As the original wiring had long since gone and the wiring currently in the car was beyond saving, plus there was no battery, battery cables, light bulbs etc I thought a rewire was the best option. also to convert the Austin to 12v at the same time seemed sensible! I used a modern thin wall cable, this gives a higher surface area of conductor whilst remaining the same overall thickness and also used PVC flexible trunking to conceal the cables. The thought (plus the cost) of using metal armoured cable went against my principles! just imagined cables shorting out etc. Also by changing to 12v the current carrying capacity of each cable was reduced by 50% . Wiring is quite straightforward with holes suitable for the trunking over most of the car. I am also installing a battery isolator switch with removable key under the seat. All lights, horn, indicators will be relay operated with individual fuses hidden up under the dashboard. There will also be a fuse in the 12v supply from the nut on the starter motor for lights, dash etc.The standard bulkhead regulator will be left in the car but not used (it's 6v anyway) and a new modern regulator fitted under the seat fitted. The car will also have a Lucas sports coil fitted (old one was missing) plus the sports coil should be more efficient and produce a bigger spark. Have bought a modern electronic klaxon, shaped much like a Rist but only £12. Initial electrical problems were with the starter  hopefully soon resolved.