The fret work of this concertina differs from the lachenals I know.
http://www.ebay.co.uk/itm/ANTIQUE-21-KEY-CONCERTINA-WITH-ORIGINAL-CASE-NO-RESERVE-/111010731565?pt=UK_MusicalInstr_Keyboard_RL&hash=item19d8c1562d
J.Gregory was a dealer, not a maker.
Who could have been making this concertina?