Motoring: Question of speed

I should have used the Discovery 3 to tow an ancient and heavy horse-trailer loaded with well over a ton of logs. Its V6 direct-injection diesel, with plenty of low-end torque, would have smiled; in low ratio first, on rough ground, it pulls it on tickover. But I felt it was time the 39-year-old Series 3 Land Rover — 2,286cc petrol, straight four — had a run-out.