“Before the court can interfere it must be shown that the judge has either erred in principle in his approach, or has left out of account, or taken into account, some feature that he should, or should not, have considered, or that his decision is wholly wrong because the court is forced to the conclusion that he has not balanced the various factors in the scale.”
“exceeded the generous ambit within which reasonable disagreement is possible.”
“23. What is a reasonable amount will depend on the circumstances, the chief of which is that there will, by definition, have been no detailed assessment and thus an element of uncertainty, the extent of which may differ widely from case to case as to what will be allowed on detailed assessment. Any sum will have to be an estimate. A reasonable sum would often be one that was an estimate of the likely level of recovery subject, as the costs claimants accept, to an appropriate margin to allow for error in the estimation. This can be done by taking the lowest figure in a likely range or making a deduction from a single estimated figure or perhaps from the lowest figure in the range if the range itself is not very broad. “24. In determining whether to order any payment and its amount, account needs to be taken of all relevant factors including the likelihood (if it can be assessed) of the claimants being awarded the costs that they seek or a lesser and if so what proportion of them; the difficulty, if any, that may be faced in recovering those costs; the likelihood of a successful appeal; the means of the parties; the imminence of any assessment; any relevant delay and whether the paying party will have any difficulty in recovery in the case of any overpayment.”