I don't know if anyone else might find this useful, but here is the .pdf file of a button diagram that I developed to help me find my way around an EC treble.
PDF 48 button V2
It has two features:
1) It tries to show the location of each button as a note on the staff (some other button diagrams already show this so this is not novel).
2) It can be used to work out the interval between buttons on the concertina or to find a specific interval from a button.
On the left hand side of each button is a number starting at 0 for the lowest note (low G) incrementing by 1 for each semi-tone up to 41 for the highest note (high C). To work out the interval between two notes you subtract the smaller number from the larger number and then look up the difference in the Table of Intervals on the diagram.
For example, E6 to B5 is 33-28 = 5 which is a perfect 4th.
Conversely, to find an interval up/down from a button you add/subtract the number in the interval table to the number alongside the note.
For example, the minor 6th down from D5 is 19-8=11 which is the number alongside F#
I offer this with some trepidation as I may have messed up my music theory. If it is wrong, or has mistakes then please let me know and I will try to correct them. If you have suggestions for a better way to present the information then I would welcome that too.
I drew this diagram with Inkscape, an open source vector drawing program. Here is the .svg file that Inkscape uses. If you download this file then you can edit the diagram yourself if you wish.
(If the .pdf file does not display well in your PDF viewer then try another viewer if you can, or just click on the SVG link above to display the diagram inside your browser).