Just finally connected everything together...
When I switch the ignition on the ECU light comes on and flashes continously..
If I disconect the battery and reconnect it still does it.
I haven't got the pins shorted to flash any codes out..
After reading the "infernal omega....flashing engine warning light, wont start" thread, the one second interval thing makes sense.
Looks like I'll have to tow it to vauxhall...
Does the tech 2 thing plug into the socket in the fuse box?
At first it sounds like the ECU is flashing out the fault codes, which means pins A and B (or is it K) have been shorting out at the ALDL plug, or somewhere down the line (ie squashed/damaged cabel form).
Now sorted after a trip to vauxhall dealer and a chat with a mechanic.
The original astra key and the one that came taped to the ECU both contain transponders. The ECU is programmed with the transponder code and will flash continously if the wrong code is received.
I swapped the transponders over and also the little receiver unit on the ignition lock and it seems to have stopped it flashing