Gemini immobilizer problem vauxhall senator 3Li 1989 reg.H23 BNC?

How can I fix my gemini car alarm which has been fitted to a 1989 vauxhal senator. I have replaced the existing battery and have also replaced the battery in the existing gemini key fob(supplied to me by the previous owner). I am unable to find a reference number in the previous owners correspondance. Therefore i am unable to drive the car as the hazard lights continue to operate even although i have used the keys to open the car manually. Could you therefore supply me with a new fob and furthermore give advice on what I can do.