16 h where do the wires go?

Number 1: the live wire was clipped to follow round the right side edge of the rear mudguard, using U shaped spring steel clips (probably by Terry Clips) at about 9 inches intervals.

This picture shows the original (vintagenorton.com)

Best advice I can offer is - if you need a new wiring harness and can't find a NOS one, just make your own. The 16H is pretty simple. Just run the cables shown in the original workshop manual schematic and use your imagination for the best cable runs (i.e. hidden from view, unlikely to be damaged by stones thrown by tyres etc).  Bind loose cables with black tape - it will look very convincing.  Unless you are going for 100% originality, this should work really well.

I sell a kit of wires and connectors, they aren't the original colours but 1960s standards. Do NOT cover with black STICKY tape, as soon as it gets wet it comes adrift-rubbish. My kit includes self amalgamating tape and tubing, see  aoservices.co.uk  The original 16H probably did not include a stop light, an 'original' loom will therefore not, so do you have a stop light? My kit includes the stop light wires.

I can and often do sell abroad. But earlier in this post was the mentioning of getting this bike going, which can be done as it is magneto ignition. So it can be run, ignition timing sorted, oil system, tickover carburation sorted without any wires, lights or battery.

Further to this...I just dug out a picture of my wiring.  It's still conducting electricity after 88 years.
(the bit of wood is propping up the tank...this has a panel tank which makes access a bit more complicated...)

I rewired a 16H recently and found a company that sells neoprene cable sleeving which is very much like the original sleeving, the 10mm ID was the closest.

  https://hilltop-products.co.uk/cable-sleeving-protection/rubber-tubing/neoprene-rubber-tubings-sleeves/neoprene-rubber-chloroprene-tubing-black.html

Darren...looks good, especially for the wiring to the front lamp where it's so visible.