I'm NOT an idiot! (at least this time)
I got a little more traction on this topic posted on another forum but was still getting no positive results. After a few emails back and forth with Albertronic in NL they supplied me with a test procedure for verifying the function of the FI trigger wires as follows:
"Take a LED and a resistor of 1k Ohm.
Make a connection from the + 12 Volt battery to the 1k Resistor.
Make a connection from the resistor to the Anode of the LED.
Make a connection from the Cathode of the LED to one of the IE wires of the distributor.
Rotate the ignition and the LED will flash."

Also (not mentioned) the dist body need to be grounded to the power source. Additionally the red ignition wire should be connected to power.
When first tested I didn't have the red wire connected to power and got no light on the white wire and constant light on the yellow wire.
With the red ignition wire powered the white wire signaled twice per 360° (as I suspect it should) but the yellow wire remained lit constantly.
So, the unit is faulty and will be repaired or replaced. A bit frustrating for sure but also nice to know it was not me making a silly mistake.
Thanks for all your help and suggestions!
Carry on,
Dave