IR35 wouldn't have to apply given that you are working for an Irish company and the company would be allowed to deduct all sorts of tax allowable expenses. There is no IR35 in Ireland.
The problem seems to be that "BRK 3" are not concerned with reducing a contractors tax liability but only to get them paid.
When you think about it CXC, McNamaras and Redstone all conveniently charge 3%, a blatant bit of price fixing, they also all operate the same questionable multi director format. In this way then all contractor pilots pay the same amount of tax.
I came accross another firm in Ireland who recomend setting up single member irish companies and they also help the pilot claim significantly more tax allowable expenses which means that the pilot pays less tax.
If BRK allowed the contractors to appoint their own tax adviser then nobody would use McNamaras and CXC and BRK would loose out on all of those kick backs and commissions that they are getting now.
The FO I have been helping has worked out that he will be paying about £50 extra per month in accountancy fees that he would do if he could pick his own accountant and also about £650 per month in extra tax. He also reckons he will have to pay a UK accountant to prepare his tax return over here. None of the "Brookfield 3" will do anything other than deal with the Irish tax office. On an FO salary £700 a month is a lot of money to be throwing away.
I think he is nuts but I apreciate the consequences of trying to stand up to BRK.