I think that the immobiliser ring is the most likely, even though you had it replaced 2 years ago. Some have had this problem repeatedly and others not at all. So, it seem to be an unreliable component. I believe Dave W has given advice in the past about first holding the key against the ring for a few seconds and then starting within 30 seconds.
I thought the immobiliser ring problem happened to certain Plus 4’s only. GDI’s.?
