If you do a lot of normal driving, keep the disco. You already have a car that is up to the job, so why spend out so much more on something that isn't going to be much better? If I were you, I'd just spend a little extra on modding your disco to make it even better.

Also, the 110 is less capable than a 90 due to having a longer wheelbase and poorer maneuverability.

i think i am leaning to keeping the disco and modding it. if i put a 1 inch lift would that allow me to fit bfgs without a problem. not big mud pluggers just a/t and would it b ok for the angle of the radius arms but one thing that is still making me think defender might b better is the oil in the ecu thing. dont td5 defenders hav tc and hill decent and the ecu problem as they ar the same engine that is my only worry if i am thinking of doing expedtions is something like that happening wots everyones opinion on td5 engine reliabliaty wise thanks

The main issue with the TD5 is not reliability. It's actually more reliable than the 300 tdi according to reliability index. The main problem with the TD5 is that it's too modern/advanced for many home DIY mechanics. This can obviously lead to expensive garage bills, bills they wouldn't have had to pay out for if they could have done the work themselves.

Older engines on the other hand are generally easier to work on as they're less complex and most people on here have basic mechanical knowledge, meaning that they can maintain their older vehicles without a problem. That doesn't mean to say that the older engines are more reliable, they're just easier to fix when they go wrong.