Got it to work, thank you.
I unplugged the two black wires that connected together perfectly.
Connected one of them to the appropriate pin on the multi pin black connector and set key to On.
Photo attached. That's a bent paperclip you can see linking them together.
Engine Check light is now flashing like a drunken xmas tree.
I've posted a YouTube video of the flashing lights and attached a photo showing the connectors required to get this to work.
Video can be found here :
https://www.youtube.com/watch?v=GPDNU9ZeqOw
I interpret the codes to be : 23, 12 & 37
These are :
23 = abnormal voltage from air flow sensor
12 = abnormal signal from ignition switch (
http://www.subaru-svx.net/forum/showthread.php?t=62748)
37 = O2 sensor 2 inoperative
I'll clear the codes now and see what comes back after my 250km round trip tomorrow.
Looks like I'll replace the air flow sensor & O2 sensors