Milltown, Raconrath, Westmeath

My ancestors Michael Moran and Catherine Kelly married in Milltown RC Church on 26 Feb 1816. Their known children were -

Christopher bapt. 4 Feb 1818

Patrick bapt. abt 1826

Eliza bapt. 14 Dec 1827

Michael Moran was convicted and sent to Port Jackson on the Ferguson in 1829.

In 1837 he applied to have his wife and four children sent to Australia.

His wife Catherine and daughter Eliza arrived in Sydney on the "Isabella" in July 1840 followed by his son, Patrick, on the "King William" in August 1840.

Son, Christopher, committed a crime to join his family, but was sent to Tasmania instead and its not known if he every found the rest of his family.

There is a gap of 8 years between two of the children and its expected that's where the 4th child would have arrived.

Can anyone help with identifiying the 4th child who would have been classed as an adult and not eligible to be sent with the family.

Thanks,