(i) There is both an expectation, and good reason, why a council declines to defend the validity of a consent which it issued (reference is made to the principles summarised in Cutliffe v Lithgow City Council in particular at [27] - [35].
(ii) Ordinarily, absence of participation will exculpate a party from the ordinary costs consequences which would or may otherwise flow from participation ( Our Town FM v The Australian Broadcasting Tribunal (No 3) (1987) 77 ALR 609 at 611-2).
(iii) Whilst invalidity of the present consent is formally the council's fault (see separate argument at (ix) below, as to the role of Mrs Westgeest's shadow diagrams and Statement of Environmental Effects) the council did not argue in support of the consent. The overwhelming bulk of argument at trial was on discretion, as propounded by her.
(iv) The council's liability for costs ought be limited to those costs which would have been necessarily incurred to obtain, by evidence and argument, a declaration as to invalidity ( Cutliffe , at [31]).
(v) It cannot be said that the council caused Mrs Westgeest to incur the costs of the failed discretion argument; Mrs Westgeest's course was entirely of her own choosing and doing (at [21]).
(vi) Hence, the council should not be liable to indemnify for those costs incurred pursuing the unsuccessful argument on discretion, in and for which it played no role.
(vii) The applicants' success on the discretion argument arose from the Court's rejection of Mrs Westgeest's submission thereon; it did not arise from fault on the part of the council, or any unreasonable pleading on the council's part ( Cutliffe at [43]).
(viii) If each respondent had defended the claim by the applicant of invalidity, and were equally unsuccessful, then (other things being equal) an order of equal responsibility (of each respondent) for the applicant's costs may have been appropriate. However, the pertinent circumstance here is that no defence was raised by the council or the other party to the consent (viz, Mrs Westgeest) - rather, there was a concession of invalidity by the parties at trial, and an implicit concession in the council's submitting appearance, and thereafter a hearing devoted to the issue of discretion.
(ix) As to the costs the council should bear (per paragraph (iv) above) it is not irrelevant that a contributing cause (even if minor) to council's error was Mrs Westgeest's shadow diagrams and Statement of Environmental Effects.
9 The applicants and Mrs Westgeest's costs submissions criticise the conduct of the council in processing the development application, in dealing with the applicants' complaint after construction started, and during the proceedings. Their submissions, which I will generally amalgamate, are to the following effect.