He subsequently undertook a Grand Tour[1] In the 1761 general election Penton was returned unopposed as Member of Parliament for Winchester, which his father had represented since 1747.
His father died in 1762 and left him Eastgate House and his estate which included a large area in the north of London.
In 1778 he entertained George III and Queen Charlotte for two nights at Eastgate House on their visit to Winchester.
[2] However he was replaced at the Admiralty in April 1782 and his domestic circumstances were troubled at this time as his wife left him when she discovered his relationship with her maid.
In January 1796 he had expressed a wish to retire and Portland recommended Viscount Palmerston to him as meeting every requirement except ‘consanguinity’.
He subsequently sold Eastgate House and estate to Sir Henry Paulet St. John Mildmay.
[4] Penton owned an area of open countryside adjacent to the New Road in North London and developed a number of streets there in the 1770s.
[6] Penton acquired social stigma from his liaison with his wife's maid Catherine Judd of Stratford-on-Avon.