@Bodgeitandscarper , I've just looked at four different tops, and all are finished differently. The bought one, has satin binding, but folded over to the front, then stitched.
Two are drape necks and the one which is more of a cowl, I have left unfinished inside. The other which is a shallow drape, is just a very fine hem.
The last is a Burda t shirt style, and I doubled the binding, sewed to the right side (O/L) and pressed it up, it looks good.
Yours looks more difficult, because of the over lay design. Could you unpick come of the overlay to get yourself a piece of flat self binding to work with?
If you would like pics of my tops, I can do that.
Jessie