Sony DVD RDR HXD710 - stuck tray - help me open it?

The machine was working just fine. I was checking what was on some unlabelled DVDs. In time I put this one in (correctly) and it went to load. It failed to load and the machine went into recovery. Upon recovery it went to load, failed, went into recovery and so on and so on. Manual recovery (holding off for 10 secs) just shorts the process...and then it tries to load again and fail and....so on. Remote it being ignored. Off button and eject button and stop button all make no inroads. Its just in a never ending loop of loading and failing and recovering and loading...
Any ideas on how I can stop this and get the tray to open? The tray is not "locked" and no other warning is showing on the display. Just WELCOME...RECOVERY...LOAD...WELCOME...

Any help much appreciated.

Thanks

Emma T