The photo shows the same arrangement as on my old '96 Omega. Same black box under the ignition. It has a collar on top that acts as a housing/pickup for the ignition barrel. Did you try unplugging the connector and cleaning the contacts with some pure isopropanal (isopropyl alcohol)?
It also seems that there is a
fault with Omegas whereby "
The infrared remote control does not function at times, even after replacement of the batteries, making deactivation of the immobiliser impossible.". The solution is to program a newer unaffected remote to the car. This requires a TECH interface.
Vehicles affected have a VIN number between 'W0Lnnnnnn R1 000001' and 'WOLnnnnnn S1 072158'. R or S are the 10th characters of the VIN and represent the model year spec the car was built to. R=1994 and S=1995. T=1996 and would be unaffected. Does your car fall within the affected range? Although it's hard to imagine the car got to this age without the problem coming to light.