“It would not be enough for Craneheath to show that there have been errors at some stage of the valuation unless they can also show that the final valuation was wrong”
“the plaintiff will by that stage have discharged an evidential burden. It will be for the defendant to show that, notwithstanding that the valuation is outside the range within which careful and competent valuers may reasonably differ, he nonetheless exercised the degree of care and skill which was appropriate in the circumstances.”