I agree that Samuel's parents were William Kidman and Bridget Sullivan. I believe William to have been baptised 29 Ja 1815 in Radford, Nottinghamshire.I then suspect William was transported in 1837 to New South Wales on the Prince George. Whilst a prisoner he lived at Queanbeyan getting a Ticket of Leave 41/1397 and Certificate of Freedom 46/0112. Once free he married Bridget.I have yet to find the court records in the UK.
Another William Kidman immigrated to NSW in 1865 on the Trebolgan aged 28 (state archive reels 2140, 2483). Maybe he was the one who married Ann Cooper in NSW at the end of that year?We would need to see if that marriage certificate gave any clues as to whether this William was the 1815 or the 1836/7 one.I suspect that William born 1836/7 was the nephew of William born 1815.