It had run through my mind that perhaps Isaac and James are the same person.
I need to list the births to get them straight in my own mind!

JENNER Births:
V18531605 56/1853 Ann JENNER, parents: JAMES, PHILADELPHIA
V18541876 42A/1854 James JENNER, parents: ISAAC, PHILIA
V18551949 42A/1855 Anne S JENNER, parents: ISAAC, PHILADELPHIA
4119/1857 Eliza JENNER, parents: ISAAC, PHILADELPHIA, reg ARMIDALE
4271/1858 Isaac JENNER, parents ISAAC, PHILADELPHIA, reg at ARMIDALE
10505/1859 George JENNER, parents: JAMES, PHILIDELPHIA, reg ORANGE
4392/1860 Daniel JENNER, parents: ISAAC, PHILADELPHIA, reg ARMIDALE
4495/1863 Edward T JENNER ,parents: ISAAC, PHILADELPHIA, reg ARMIDALE
And, perhaps, Sarah perhaps 1862
And then these two

4763/1864 Caroline JENNER, parents: ISAAC, PHILLIS, reg ARMIDALE
4800/1866 Barbara JENNER, parents: ISAAC, PHILLIS, reg ARMIDALE, Died 1867, reg Armidale
There are deaths for
Isaac (1921, Granville) and
Daniel (1936, Manilla) JENNER - both with parent names given as Isaac and Phyllis, and also for
James JENNER (1934, Granville) , parents given as Isaac and Phillip (!)
Judith