Good question. I did the same class 3 in Canada in 2010, and was unsecure if i was gonna do the class1 at the same time, due my hearing loss too.
When I returned back home to Norway later, I booked a class 1 medical FAA, and my hearing-test was only to stand face to wall from the doctor, reapeating his words, and it was all good!
To do the JAR-FCL -medic, it's really pricy,m but you can pay seperatly for the hearing-test if you think that will be an issue, so that you don't have to pay for the whole test if you fail the hearing test...
Good luck!