John Charles Bowring

I am trying to find a photo or drawing of John Charles Bowring (son of Sir John), but so far without success. He was in Hong Kong from 1842 as a partner of Jardine Matheson and a keen collector of beetles. He retired to Exeter in the 1860s and became a Justice of the Peace. None of the logical sources seem to have his image, although illustrations of his father and brothers are relatively easy to find. Can anybody help?

Simon