G'day Mr Red,

In some quarters, same note in and out is called 'single action' and the alternative 'double action' (... just a little too close to the operating systems of pistols ...). Anyway, this is confused by Wheatstone calling large English system concertinas (basses, specially voiced 'clarinet' or 'oboe' models &c) that sound on the push and have huge 'flap valves' to refill the bellows quickly on the draw ... 'single action'.

There seems to be no agreed term - and folk musicians are too indivualistic for one to appear in the near future.

Regard(les)s,

Bob Bolton