Xen VM - Ubuntu fails to boot, how can I enter recovery mode?

I have a Ubuntu 14.04 VM that failed. It could not red/write, so I rebooted.

It now loads as far as this:

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* Starting userspace bootsplash                                         [ OK ]
Checking disk drives for errors. This may take several minutes.
keys:Press C to cancel all checks in progress

keys:
Errors were found while checking the disk drive for /.
keys:Press F to attempt to fix the errors, I to ignore, S to skip mounting, or M for manual recovery
 * Stopping userspace bootsplash                                         [ OK ]

 * Starting Send an event to indicate plymouth is up                     [ OK ]
 * Stopping Send an event to indicate plymouth is up                     [ OK ]

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It then hangs.

The system boots to fast to see grub or much of the boot process. It goes straight past:

Press F to attempt to fix the errors, I to ignore, S to skip mounting, or M for manual recover

So I do not get chance to press a key.

How can I recover this system?