"Where the court orders a party to pay costs subject to detailed assessment, it will order that party to pay a reasonable sum on account of cost unless there is good reason to do so."
"The Claimants shall pay the Quantum Defendants their costs of and caused by the said amendments to the Points of Claim."
"(i) Despite occasional references to a possible distinction between jurisdiction and discretion in the operation ofCPR 3.1 (7), there is in all probability no line to be drawn between the two. The rule is apparently broad and unfettered, butconsiderations of finality, the undesirability of allowinglitigants to have two bites at the cherry, and the need to avoidundermining the concept of appeal, all push towards aprincipled curtailment of an otherwise apparently opendiscretion. Whether that curtailment goes even further in the case of a final order does not arise in this appeal. (ii) The cases all warn against an attempt at an exhaustive definition of the circumstances in which a principled exercise of the discretion may arise. Subject to that, however, thejurisprudence has laid down firm guidance as to the primarycircumstances in which the discretion may, as a matter ofprinciple, be appropriately exercised, namely normally only (a)where there has been a material change of circumstances sincethe order was made, or (b) where the facts on which theoriginal decision was made were (innocently or otherwise)misstated."