Hi Carl, I hope this finds you as I see you haven't posted in a few years. I have been researching my Hierons family links also and don't know whether we can help each other but heres my history...
me - Kimberley Sullivan
my father - Robert Sullivan
his mother - Alice Harrison
her mother - Maud Mignonette Patten
her mother - Elizabeth Ann Hierons (born 1860 in Victoria, Australia)
her father - William James Hierons (born 1831, Somerset, England, immigrated to Australia in 1852 with his wife Eliza Copenhagen)
...and that is as far as I can get. Hierons is proving to be quite an uncommon surname, and thus very difficut to find and info on, until I stumbled upon your website. Well done by the way, its great! Although we may not connect any of our ancestors yet, with this surname there must be a connection somewhere. If you want to chat, my email is firstname.lastname@example.org