The standard TDi here weaves like a bastard at any speed over about 38 when towing another disco on the big trailer. This despite loading it tother way around to make it balance better - nose weight about 50 Kg, estimated.
silly thing is, the disco I've just sold would tow the trailer with the TDi one on it much better.
The only difference was my tweaks to the suspension.
Perhaps the standard suspension is too soft?
the TDi had new dampers not that long ago, but only cheapo "paddock specials" so I doubt they're up to much, but they're not completely shagged, either, and mine had the same dampers on it.
The 110 only used to snake with the trailer loaded wrong, and too much noseweight.