Hi Viv , you seem to be showing family that disappeared. Have you checked the US, Canada and Australia.
There is a notice in a Tasmanian Newspaper 1/9/1849 of a Marriage of John Kewley, Master Tailor , in Perth W.A., he is shown as the eldest son of Phillip Kewley of the IOM.
As this was in a Tasmanian NP , he may be the convict John Kewley who received a Ticket of Leave 11/11/1842.
There is a Robert Kewley who joined the Police Force in the State of South Australia 1/2/1849.
There are many more Kewleys in the State of Victoria in the 1840's.
Just a thought

Cheers
David Dwyer