Dear Annette,
HJH Exall was my ggmother's father. HJH Exall was married Sarah ?? My ggmother, Clara Exall, married a Charles Ferguson, who we think lodged as a young man in Sarah Exall's house along with my ggrandfather.
Clara had a son, Alfred Francis Ferguson, who was brought up by Clara's sister, Almeira. Charles disappeared and my ggranddad stepped in and "married" her, they went on to have several more children. Anne Jones, who has previously corresponded with you is my cousin and is directly descended from Alfred Francis Ferguson who later took the family name Jones. He was also a painter and died when the roof he was painting in Charing Cross station collapsed.
The family story is that HJH Exall painted the ceiling in St Paul's cathedral. I don't know if Anne has added to her tree recently, but it may be worth you taking a look because Anne is much more efficient than me. If we do find out anything more about HJH Exall's ancestors we will let you know.
Best wishes
Gillian