Except for the very first CD players (which used an LED and photodetector to see if a disk was in), CD players work like this:
1) You put the disk in.
2) The laser tracks to the inside edge of the disk (where it hits a limit switch).
3) The laser then tries to focus on the disk.
4) If it can't get a focus lock then it decides there's no disk inserted.
5) Only once it's focused on the disk is the disk actually rotated, when the laser then tries to read the TOC.
There you go again being pompous Nigel. Many transports give the motor a little kick even when there is no disc inserted. That doesn't really square with your scenario. I do work with them all day long and I just might know a thing or two.
I repair them all day long - and almost all CD players don't move the disc at all until the laser has focused on the disk - I can't even remember the last time I saw one that did?, but probably not this century.
As for 'pompous', perhaps you might try reading your original post?.
The first thing to do is try changing the laser assembly. most are made by Sony, or are copies of Sony lasers - they start KSS??? - a typical example being KSS210 or KSS240.