My understanding of the phrase 'Written music figured in an easy style for concertina' doesn't suggest tablature; rather, music arranged to be playable on a concertina as opposed to, say. a piano arrangement which just wouldn't work...

The English concertina system was specifically designed by Charles Wheatstone to facilitate reading music - the 'lines' are on the left, and the 'spaces' on the right - thus eliminating the need for tablature.

The Anglo lends itself to 'ear' playing more readily; I think one would have to be extremely dedicated to want to play from standard notation... I tend to read the music and play by ear... but then, I was trained in sight-singing!