MK4 locked up!

[z1399uk]

HELP!!! Life often comes down hard when all is going so well!
Ive been doing upgrades on BMW satnav for a few years now and I havent come across a mk4 holding onto a map disc as has just occurred, usually its the mk3 that does that. Any suggestions as to how the disc can come out without dismantling the unit?
I had just burned a 2008-2 from a DVD DL to a single DVD, removing all the foreign stuff as appropriate, and loaded it into the satnav. All worked well, no delays, looked great. Switched off and went indoors. Came back to remove the disc and replace with another version with speed cameras and checked the monitor before removal and it asked whether I wanted to continue the journey. I clicked no, then I was informed no disc in the drive (oh yes there is). Then tried to eject the disc to no avail, no sound from the drive unit.
Please advise chaps