I still only have around 25 hours on the D120A, but my experiments at Southern English airfield elevations (a few hundred feet AMSL), middling temps (5-20C) and windspeeds (5-15kt) suggest around 200m for T/O and 300m for landing (with no wheel-braking, but airbrakes deployed). Does this sound reasonable to everyone?
What is noticeable is whether the airbrakes are deployed or not. With airspeed not nailed to 45kt over the hedge and her attitude not spot-on in the flare, it seems you can easily add another 100m to the landing roll if you're not careful.