Update to my problem below.

It's now working very well. I had a conversation with a very helpful tech guy at Performance Ignition Services (number given to me by Hurricane Automotive in Geelong who made the longer 9mm distributor to coil HT cable).
Anyway, Performance suggested that the wire I had made might be picking up a signal from a different source (sure enough I had it running too close to the left bank of spark plug cables) and that the connection wires were probably too long.
As a fix, suggested that I shield the wires and ground the shield (this was mentioned further back in this thread I remember now), and twist the wires together for the run, keep the length as short as possible and keep them away from interference.

I dug through the spares box, and found the D1 3.9 distributor I have still had the connection wire for the remote ign module. It is already twisted and shielded with a ground connection, and the plug actually fits to the two terminals on the Bosch 024. I did pull them out of the plug and solder them first though. Soldered two new 3.2mm spade terminals onto the dist end of the wires.

Pics attached of the working unit.
I made a fitted heat sink plate from 5mm aluminium for the left compartment that some use for a second battery (my second is inside), doubled the 5mm for the mounts to improve the heat sink - used heat sink paste for the joints. I cut up an old Lucas module mount and made a kind of holder for the wires on the distributor, keeps them stable and will prevent pull out. The wires finally run between the alternator and the PS pump, there is nothing else electical anywhere near.

As I mentioned, all good, and with a working vacuum advance feels so much stronger than before.