Only thing I'd suggest is tap into the RBL on this one. They exist for people like you, and have, most certainly, dealt with these claims before. Don't worry about the deception, you're not the first. There are also other threads related to hearing loss, where you can ask others for their stories.
If you approach the Royal British Legion (I would recommend you do), then make sure you go to the right people i.e. County Headquarters or the POP UP Centres in the nominated towns and ask to speak to the Welfare Rep.
Do not wander into the nearest Royal British Legion Club, full of non serving civi's and ask as you may get duff info.
If you are in the Beds, Bucks, Oxfordshire area send me a PM and I will send the details of who to speak to.