At the moment I have Knoppix 8.1 inside a DVD and a 16GB USB stick if I must download another rescue OS

I also have 2TB external hard disk.

I am aware of the size of the partition which is 900GB and it is NTFS

I have tried TestDisk but it is taking too long and it is only coming up with a lot of EXT3 partitions, and only three NTFS partitions of 3GB

It appears some sectors are also damaged, and I must use a way where it can bypass bad sectors. It is fine with me if I end up throwing away this hard disk.

Thanks a lot, experts at Linux Questions!

Not sure there is a fool proof way. Might consider making a dd copy of the drive from a known good system. This system may have issues.

Not sure any rescue disk will be fast. They may not attach at the fastest way to the drive.

Other ideas may be
http://www.system-rescue-cd.org/
or
http://www.ultimatebootcd.com/

Many live cd/dvd/usb's can download programs while live to assist you even if not included on the disc.

Bad sectors should be automatically reassigned. If you keep getting new ones, the disk is probably scrap metal.
If you have data you need within bad sectors (say a partition table, or filesystem meta-data), you are in real strife. That's why we all take backups.
ddrescue may help you get an image of the disk you can use for attempts at recovery.

What does "smartctl -A /dev/<disk>" return ? Post it here.

Did you check with fdisk to see if the partition might still be there.