This charts was prepared by me, and show the layout for Wheatstone 30 button G/D anglo concertinas. This layout was also used by Lachenal.
Wheatstone 30 button G/D
This chart was prepared by Jody Kruskal, and is used by permission. As it says, it is for the Jeffries 38 button G/D anglo concertina. There is some variation among concertinas of this type, but as far as we can judge this is close to what one might call the mean average layout for concertinas of this type. The 30 button Jeffries is quite similar.