I have added the head with hair and beard along with the hand. I still need to work further on the ear, beard and hand to provide contrast and slight shape corrections.
I also added more contrast to the shadows on his apron and increased the folds where it catches on the corner of the bench.
In this composition, the figures at the back ore the real focus, along with the cooking. The two figures almost completed in the foreground just serve to frame the subject and direct the eye of the viewer.
the section on the right of the composition and, in hindsight, I may have left most of that off and enlarged the section with all the interest. Having said that, I shall not neglect that section when I paint it.

Just for interest, I have added this photo taken a few seconds later than the first, which was taken in fading natural light, with its 'blue' bias. The second was taken with the warm LED lighting of the studio on.