The Bose A20 is clearly he best option, I assume that you are in the UK and if so could claim the tax back from the HMRC as providing your employer gives you a letter saying a headset is required. There is also a H&S issue to back up the cost of the headset as you are working in a noisy environment.
You won’t get all the money back from the HMRC but it will take the sting out of the Perchace.