I got my first concertina (Lachenal(Murdoch) anglo C/G) in 1999.Also interested in miniature anglo and finally got a Norman miniature in 2009 and Jones mini in 2016. I love Irish music played in old, relaxed style. Now I am halfway done with Japanese translation of Chris's concertina FAQ.
I enjoy observing anglos on the internet, I have seen a few in Lachenal (only 8 in nearly two decades). One was a C/G anglo with the Amboyna ends, which was listed in Barleycorn last year.
A quote from Alex Holden's website:
"One of the defining characteristics of traditional concertina reed shoes is that the underside of the vent is relieved (i.e. the bottom of the slot is slightly wider than the top). My current understanding is that this allows the reed to work properly even at very low bellows pressures, i.e. it enables you to play quietly if you want to. It also has an effect on the tone. "
Please refer this page https://www.holdenconcertinas.com/reed-prototypes-part-1-frame-and-clamp/ .
In my view, it is the relieved vent slot that is important, whether screwed or riveted. I would like to know the cross-sectional shape of the slots in the DIX series. Do they slightly widen towards the bottom side?
I own earlier Jones (#1312 26 button semi-miniature), however, it does not have the features mentioned above. So yours may be a prototype.
The trap door arrangement reminds me of Henry Harley. So it might be a German origin...
Interesting. On page 33 of the book "The History of the Melodica" I found Gottlieb Kratzenstein's name and a reference to his free-reed "talking machine".
If my memory serves, Fabbrica Concertine became Concertine Italia. Their catalogue page is here:
https://www.concertineitalia.it/en/hayden-duet-46-concertina/hayden-duet-46-concertina-concertine-italia/
I believe Michael Tubridy also played in C with C/G concertina. In this clip (around 6:30) he didn't say directly though. Many concertina players were playing in C in the olden days.