I've only ever seen one sibling for Charles b. 1823 Sussex, that is a George b. abt. 1830..
No. 303 Sarah Jane daughter of Charles Furner, of Duddleswell in the Parish of Maresfield, Bricklayer, and of his wife Mary, daughter of James and Mary Waters, was born on 6 Feb 1836 and baptised on 9 Feb 1837.
I am missing some of the other baptisms. Yes, Charles 1823/24 I don't have.
Sarah Jane was the 8th. The two born between her and George died young hence 6 children arrived in NSW.