I have a six month old Irish Concertina Company Vintage. Was working fine until a week ago when I noticed the draw C# RH first button outside row, was returning a very muffled, muted sound. The push, also a C#, sounds fine. I am assuming that there is a reed problem?? How difficult is it to get to the reed. I have taken the fronts off of concertinas before, but have little experience with reed pans. I will also contact ICC. Thanks.