I read your post again and can see what you're getting at now but at the time I interpreted the 'reasonable' or 'unreasonable' judgements as following each scenario so in other words to me it sounded like "It was raining and I didn't wanna drive in the rain. Reasonable." I was just assuming that was your pattern since you ended the paragraph by talking about my ex's withholding and saying "reasonable" after. Anyway, no worries, let's move on.
My understanding of a costs order is that they are only used in fairly extreme circumstances when the claim is obviously vexatious or false and their side had to go to court unnecessarily in circumstances where they had already done all they could to ensure that the matter wasn't brought to court but you went ahead and did filed an application that was without merit anyway. I don't think that's what is happening here at all. She genuinely did withhold the children over a period of two weeks and breach the orders. So it's not like it's a false accusation. IMO the main question is whether there is a reasonable excuse for it.
I think given I've waited well over a month for that 'reasonable excuse' to be communicated to me, and my neither my ex nor her solicitor has provided one despite me having written at some length to her solicitor documenting the course of events and how my ex had numerous other options available to her that wouldn't have resulted in her needing to withhold but she chose to withhold anyway and refused to discuss it.
I perhaps need to remind you of the facts of the matter and why I think she didn't have a reasonable excuse. The main reason I'm still upset about her withholding is that it was systematic and clearly opportunistic. As soon as one justification expired or was otherwise disproven, she moved on to a new justification. This happened at least 3 times, and then her final 'game set match' justification (in your mind anyway) was quoting an obscure line in a DHHS article that said you should 'stay at home if you still have respiratory tract symptoms', but at no point in time did she ever actually demonstrate that the children HAD these symptoms or get any independent confirmation of them. She merely claimed it was true and used a doctor to write a generic letter saying "the mother told me the child has symptoms". I actually spoke to the doctor following this letter and he confirmed that he didn't see the symptoms, he effectively just wrote the letter to satisfy the mum.
So in those circumstances, and with an affidavit explaining all this in all the necessary detail, I'm pretty sure that if the justice system is remotely fair the judge would recognise that I was the one taking the steps to avoid going to court and she was the one playing power games, trying her very best to keep the children with her at all costs even when common sense would suggest there was little to no risk to public health. I gave her plenty of time to seek legal advice and respond. It was in fact her side that in put up a communication brick wall despite assurances that a response letter would be forthcoming. And despite me writing numerous follow up emails to her lawyer asking for the formal response that was promised by him, I got no further correspondence on the matter for an entire month. So if after all that, after getting nowhere in attempting to avoid court, did I file a contravention application as a last resort. In those circumstances, I can't see how I should have to pay costs. I've been the reasonable party here IMO.