Ignition wiring... problem with 12v permanent supply

Hi all.
I'm trying to wire up a new ignition.
For some reason the 12v permanent supply (brown wire) is only giving a reading of 5volts... obviously when i turn the ignition on, nothing happens.
I'm guessing the brown wire must have been burnt out somewhere to give such a low voltage reading...

so... I've put in a bypass wire direct from the battery positive to the ignition, another bypass wire to starter relay and also spliced a direct feed 12v to the glow plug timer.
The plugs are working, getting hot. The stop solenoid (or shuttof valve) is receiving 12v ( at least in postion 1 of the ignition), the starter turns the engine over well.... and it's receiving fuel.

However it doesnt show any signs of firing up.
The ignition is the old lucas type with 5 lugs on it (two big ones and three smaller) - it's an 84 defender. However it has a 200tdi fitted

Is there anything else, electrically that would prevent the engine starting? I can't think of anything... unless somehow the solenoid is shutting off in position 2 when i actually crank it - which i haven't tested for yet.

Any thoughts or suggestions? Cheers

UPDATE...
I feel a bit of pratt now but it turns out i had the wires all wrong on the ignition (duff info from google.... i should have used my multimeter!)

So yes, the solenoid was cutting off during cranking due to this.

Engine starting fine now on the bypass wires.

This still leaves the question of the 5v reading on the original brown wire (permanent supply). Could this be correct?

Tomorrow I will take off my bypass wires and try the original wiring again... see if it works

OK... so I put the original connections back in place - and all works fine! No longer getting a 5V reading on the supply to ignition. I can only conclude that it was a bad reading, i.e. negative prong of multimeter not earthing properly!

For anyone else who has a 200tdi fitted with the old lucas 162S ignition, the numbered pins are as follows:

5 - 12v supply (brown)
4 - Starter relay (White/.Red) [connects to pin 5 on cranking]
3 - Ignition ON position - power to fuel solenoid & glow plug relay (White) [connects to pin 5 in 1st postion and on cranking]
2 - not used (believe this was the glow plug feed on older non-turbo defenders) [only connects to pin 5 on cranking]
1 - Radio (black/white or orange/white) [connects to pin 5 in 1st position, disconnects on cranking]

Best to make a note and diagram of these as you can't see the numbers when fitting the igntiion to the steering column!