There are two Australian POPPLEWELL lines going back to YKS about this time.
The first, about which little is known, descends from a David POPPLEWELL, convict, who was transported to Tasmania in the 1820s.
The second, my line, descends from a stonemason, Joseph POPPLEWELL, who was the son of Benjamin POPPLEWELL & Esther HARTLEY, and a grandson of Joseph POPPLEWELL and Jane GELDARD.
Joseph was born May 5th, 1799 at Methley, YKS (bapt May 26th), and arrived in Sydney in 1835. Two marriages and quite a few kids later, he converted to Mormonism in 1853 and sailed for SLC (with family and step-family in tow), but only made it as far as CA. They all returned to Sydney in 1856 (no longer Mormons) except for his eldest step daughter, who married and remained in CA (descendants have been traced). Joseph died in 1872.
Benjamin seems to be a christian name which runs through this branch of the family last century - might just be a link between the AUS line and your line?