If people want a photographic likeness type portrait- well there are plenty of photographs available.
I think the physical portrait of the head is superb, one of the best I have seen, and it dominates the picture. The butterfly landing on his shoulder is a reference to the King's environmental concerns.
Neither age nor education has anything to do with whether someone can appreciate an item of artistic endeavour, and remarks about being a 'prole', whatever that might mean, are just affectations.
In this day of photography, the only point of a portrait like this, is for the artist to express or show something about the subject in the painting that cannot be seen in a photograph and this is what the artist has done so successfully.