mk2 zs180, turn over but no spark

[Mark S]

changed cam and crank sensors, still no spark.
changed ring to pickup code from fob also.
engine speed is being read on diags, so its seeing the crank sensor.

led in middle of dash flashes when armed, goes off when unlocked via fob and stays off when ignition is on, engine turns over but does not spark.

almost like its in a state of immobilisation.

mk2 with pektron and round 3 button fobs, both fobs will lock/unlock car.

any ideas?