DICK... I stayed quiet for a some time hoping that THIS world might get wiser meanwhile but if it hasn't I felt urged to interfere:-)
It is funny how quite experienced and knowledgable people sometimes are surprisingly blindfolded from obvious facts and even fooled by some kind of traditional confusion.Handmade musical instruments have always been subjects to much superstition ( like other handicraft in guild-spirit)even before Stradivarius and C Wheatstone is our example.
He was a notable inventor no doubt but it is known nowadays that he was not much involved in actual production of concertinas while many people in the "concertina world" still speak of him doing this or that when "making concertinas".

It would be very interesting to ask Steve directly from where he got this: "...the two combine and amplify the sound ...this gives very pure sound whithout any overtones...you don't get this in a melodeon or an accordion because the reed in those operates in a free space...they don't have this chambered arrangement"

Do you have any contact nowadays so you can ask him? I don't blame him at all - I have met experienced accordion makers believing that the accordion sound comes from the vibration of the reed and that the
pan on which the reed blocks are assembled operates like a resonance board of a piano...