The 6 CD changer in the boot of my 56 reg Octavia II Ambiente 1.9TDi DGS Automatic Hatchback (is this enough details? ) is, I assume, the bog standard one. The handbook suggests it plays MP3 files, my one doesn't although it does play ordinary cd's or (ahem) copied ones written in cd format.

The slot in the head unit plays MP3's ok.

To my question, is the bog standard 6 CD changer meant to play MP3's does anybody know?

The changer does not play MP3 disks, only the headunit.

Just to add, the only skoda changer that plays mp3 disks is the one in the audience HU.