Same Landrover as we're having the dashboard problem with, a 1991 Discovery V8i. The power steering is also playing up a bit.
Most of the time it's fine but occasionally it goes heavy, only when the engine revs are low, and becomes distinctly harder to steer.
Presumably the pressure in the power steering system is dropping, resulting in the heaviness. Is this likely to be the pump or the steering box? Maybe a new set of seals? There's no sign of any fluid loss, incidentally.
Million dollar question: Is it likely to be cheap or expensive?
Cheers Gary