Depends on the chassis range of your disco 11 auto as to whether or not you can use a stage two type chip.
The early disco 11 up to 1a chassis range as you already know get confused. However auto's built on 2a chassis range do not suffer the same problem and can be given almost as much as a Defender manual.
All this said though any improvement over the standard is a BIG improvement and if the right upgrade is used will remove the flat spot when you pull away.
Be careful some the chips just dump fuel in and make the TD5 smoke like a bitch!
Ask to see or test a vehicle before you buy, could save yer self a lot of grief...
If done proper no smoke with stage one and only a little with stage two when foot through the boards.
Hope this is some help.