As a long time player of the English Concertina I have looked at these on the Wakker Concertinas website. There is a, sort of , problem with this keyboard of concertina , both for the players and the makers ; because there are so many fine antique examples still around, and very playable after a rudimentary restoration, most players use these pre war or antique models. The main concertina market is for the Anglo , what accordion players would call diatonic boxes, and thus very few makers offer the English type and virtually nobody makes the old Duet keyboards. So, not enough market for the makers to bother with leaving the players to hunt for those instruments bought by our grandparent's generation.
It is a bit Catch 22 , old versus new.... but I have to admire Wim Wakker who , being a fine player of the 'English' concertina has developed a nice range of models as well as supplying the Anglo style and a new Duet keyboard. He also designed and organised the manufacture ( in China) of cheap 'starter' models that perhaps will boost the numbers of Concertina players world wide.
The two Concertinas I currently play were made in 1898 and 1927...