Cavendish did not follow his brothers to Eton, and his education appears to have left much to be desired. According to Lord Morpeth†, who was brother-in-law to his cousin, the 6th duke of Devonshire, he was ‘quite deficient’ at reading and writing even in 1820.
Cavendish re-entered the Commons in February 1821, when he was returned unopposed on a vacancy for Newtown, Isle of Wight, on the interest of Charles Anderson Pelham*, who was later a notable beneficiary of his father’s will.
At the 1826 general election it was widely assumed that Cavendish would offer again for Sussex, though Anderson Pelham, now 2nd Baron Yarborough, had rated his chances as ‘doubtful’ in March. His failure publicly to account for not coming forward was widely resented, while some reports ascribed his retreat to a recognition that his pro-Catholic views were unpalatable to the county.
At the 1830 general election Cavendish retired in favour of his patron’s heir. Nothing came of rumours that he planned to stand for Sussex on this occasion or at the 1831 general election, when he was returned unopposed for Yarmouth, Isle of Wight, by Yarborough, who, as the dominant trustee of the late patron’s property, had controversially arranged to accommodate supporters of the Grey ministry’s reform bill.
At the 1832 general election the additional representation given to Sussex by the Reform Act enabled Cavendish finally to claim a county seat. He came forward professing the same liberal principles and comfortably topped the poll for the eastern division.
