Yes, but keep it short and to the point, and just refer back to the court orders, also, add in a point as it is the other party who is seeking the hair follicle test be carried out, and the fact that you have had numerous negative urine samples already, and you are confident that you havent touched any drugs in the past 3 months, (also not that these hair tests even show up the codiene in cold and flu capsules, admittedly you get to sign a declaration about this prior to the test on testing day) I would put it back to the other party, and say, in the interest of moving forward, and so that we can put this bed, I will pay for the hair follicle test only if the result comes back positive for hard drugs, failing that, the other party, and/or legal aid can pay the bill in the interim as per the court orders clause (xxx) dated (xxx). This shows your willingness to facilitate the test being carried out and that you have nothing to hide, and it also lets you see how hell bent they are on getting it carried out.