I've run Foremost against a partial dd copy of the drive and it finds files, as does Photorec which is running now. I've booted another system and attached the 1Tb drive via USB, I can scan the 1TB drive using Testdisk which can see the partition data and the directories under root but all of the sub directories such as home are empty with no chance of copying any data.

Not surprisingly the system will no longer boot. If youre very very lucky, it may locate enough of the ext4fs data structures to bring the disk back to live, although probably with some missing files or other problems. I tried to rebuild the Grub file and it looks like somehow the partition table and maybe some of the root partition were overwritten. You should recover lost files to another drive than the one you are recovering from. after installation you can run PhotoRec from command line: photorec. Install TestDisk package using apt-get (package management for debian): apt-get install testdisk. This morning, I could reboot the laptop system by first booting from a USB drive, then using Grub utilities to boot the laptop, I should have made a backup at that point but. Enter 'Root'for username and welc0me is the default password. I had a problem with the Grub file and tried to rebuild it but without any luck. I have a 1TB Sata Disk in my Linux Laptop.

Totally my own fault as I pressed too many buttons without a backup, but am hoping that all is not lost.

Testdisk ext4