Boyd is not a make of concertina but was an influential name in the history of the instrument.
Harry Boyd kept a music shop in Newcastle on Tyne. He stocked both Lachenal and Wheatstone concertinas but commissioned them directly from the makers with apparently fairly strict stipulations as to quality. Hence Boyd-Lachenal and Boyd-Wheatstone concertinas are of a special quality above the factory norm even on the higher end instruments.
Later concertinas have 'H Boyd' as part of the fretwork in the metal ends. He typically specified bowing valves on all instruments and insisted on particular workmen finishing the concertinas.