Graham
Thanks for your comments.

As I said, it is difficult to implement bends as two tied notes, for various technical reasons.

Showing a fret would limit you to defining bends only of semitones or whole tones. It would also mean sometimes using two digits, when well up the frets.

I have seen the upward curving arrow, and could maybe use that, but it is more difficult to code - could delay the code release for some time.