remove immobiliser on a 1998 Astra 1.7td estate?

Purchased a 1998 Astra 1.7td recently with a plain key and no transponder key thinking this was a easy process as the car was cheap, purchased a blank transponder key and got it cut but still needs programming, dont have security pass yet as even more money.
How can I remove immobiliser of this diesel as I dont want to spend anymore money without knowing first that the engine is fine, all lights come on and engine turns over but does not fire up except for computer clock on centre console nothing shows....looked for transponder around ignition cant see it, a circular ring just below the centre of steering wheel, Help its a nightmare freddie met jason.

Darren Watson
October 2006