Think it was £96 fixed fee, I had to pay for postage to them (UK address) but they cover the return.
Have just spent another £100 or so on spares to cover another 10 years+ use! I have replaced the headband pad myself at least once before, that was simple from memory. I would have done the pads too myself and have removed them before, but thought it worth getting the full "service" in case there was any issues with the drivers. I did wonder if they would consider them BER and just replace them so not totally unexpected.