During the boot process I see the 

Starting  Symantec Encryption - Full Disk Edition version 7.0.5
Please Wait....
Preparing Pre-Windows Environment

Then when the screen changes a black scree appears with a cursor flashing in the top left hand corner of the screen, but if I type anything or press enter, its echoed to the screen.  This is where on the other installations the symantec graphic appears.

Can anyone help?

Do you have another machine of same make and model working fine ??? I don't see any compatibility issues with 705 and this machine. What I recommend you at this point is reimage the machine (if the data is not important) -- if the data is important then use access utility and backup the data on to an external HDD.

You can also try booting the machine in safe mode and check if machine boots there. If it does then check for any events in event logs.

Then update the BIOS/chipset drivers on the machine. Simply install the OS and the drivers and then install SEE. Let the machine encrypt itself completely and then reboot.

Generally speaking if the machine is encrypting itself then reboot should not cause any issue -- not sure what happened here.

Thanks for the reply

I need to get some data off there which is why I cant reimage at this time.

I cannot boot into windows safe mode as the machine doesn't get as far as loading windows.  After it has said preparing pre-windows, at this point and at the black screen that appears next, anything you type gets echoed to the screen.  When you do CTRL ALT DELETE it responds Restarting Windows.

I cant boot to the recovery or access disk.  The recovery disk that comes with 705 give a BSOD described earlier, and the access disk and a manually created recovery disks boots but then just restarts the machine.

I tried booting to the manually created recover disk to safe mode which works but the utility wont then start.

Ive updated the BIOS of the machine, still no Joy.  I was considering if there was a hardware or software drver compatbility issue between Tecra M1 and SEE.

Well it seems to be a hardware compatibility issue however I am not sure about this -- I think Symantec tech support should have an answer for you. If you wanna check this at your end then try installing see 705 on a different machine of same make and model and see how it behaves.

Also if you go ion BIOS do you have an drive operations like SATA - AHCI (like we on dell machines) .... If yes then try playing with them and see if they help.