Hi there,
I had to do the hearing test THREE Times. My left ear was fine, but my right ear I didn't hear all the beeps because he was doing his flipping paperwork on my right side. I stopped the test and told him to stop it, which he didn't appreciate but did so. The second time my left ear failed (He then figured the button was broken!) So we tried a third time and I passed. I don't like Capita, and I don't trust them. I'd speak to your AFCO and let them know that he was unprofessional in being even slightly noisy during, it is supposed to be in a sound proof room.
What I suggest is make sure you're as calm as possible before the test, speak to the doctor straight off and explain to him what happened last time round and that you'd like to do the blood pressure first (or first and last, or last, once you've passed everything else!!!)
Whilst doing the hearing test, if there is ANY noise in the room, stop the test, and request it to be quite. The hearing test is HARD, and shouldn't be made harder by external factors. I used some ear drops the week before the test to make sure I had no ear wax in my ears. Also, avoid listening to headphones or loud music in the days leading up to it. Give yourself the best chance possible.
Good luck, I'm sure it'll all be fine. I hated the medical as it's the only stage you can't really prepare for!!!