Abel, a new angle

Yet another portrait of Abel, by Jean Charles Robineau, who presumably met Abel in England. I have very little information about this painter (next to none, in fact) - has anyone got a very comprehensive 18th century art encyclopaedia?

Robineau hasn't been as kind to Abel's portliness or dishevelled looks as Gainsborough. Note that Abel is seated at a harpsichord, another instrument he was proficient in. He looks away, as if waiting for a cue to start playing the continuo to Fischer (oboe), maybe, or  Wilhelm Cramer (violin), two of his friends also belonging to the London musical sphere.