Don't think the car would run then cut out at certain revs with an immobiliser fault, think its just coincidence about the key thing.
When mine was cutting due to high pressure pump it wouldnt start immediately, I had to wait and sometimes a few turns of the key before it would fire.
When mine was cutting due to high pressure pump it wouldnt start immediately, I had to wait and sometimes a few turns of the key before it would fire.