I have no experience with the ABRSM pieces, but I have used midi files in the past. They are helpful in that whilst playing hands solo you are given some sort of idea of the context of what you are playing within the music.
Often, when learning a new piece I will create a midi recording of it using standard notation software (Like Finale notepad) to get a better idea of what it should sound like before returning to the piano. If you already have the sheet music then you could create files like these yourself. I have experimented with playing along to these files to force myself to stick to the rhythm. But ultimately I think they are just another tool available to learn the notes in the right order (!)
Interpretation being the performers own, midi files do tend to be bland souless things pretty far removed from how music should actually '
feel'. The question is for me, at what point do you begin to stamp your own personality on the music? After it is thoroughly learned, or during the process?
Sorry, this post doesn't help you much! Sunday morning, bit