You read so much specfic, maybe you can help me with my fruitless quest to find a John Lennon time travel story. Details are here, but the quick summary is:

Short story told from the POV of John Lennon. Someone had come back in time to pull him out just before he was assassinated. Definitely not Get Back: Imagine… Saving John Lennon by Donovan Day.

Please help if you can. Thanks!