After receiving his education at the neighbouring presbyterian academy at Findern, young Bentley, being then about sixteen years of age, was placed in a warehouse at Manchester to learn the processes of the woollen and cotton trades.

In 1757 he assisted in founding Warrington Academy, and in 1762 in building the Octagon Chapel in Temple Court, Liverpool, for the use of a body of Dissenters, of which he was a prominent member; they preferred a liturgy, but had scruples with regard to the use of the Athanasian Creed and other parts of the Book of Common Prayer.

In 1769 he finally left Liverpool, and after living for a short time at the warehouse in Newport Street, London, he moved to Little Cheyne Row, Chelsea, in order to be near the works which the firm had lately established there for overglaze painting.

On 22 June 1772, at All Saints, Derby, Bentley married Mary, the daughter of Mr. Stamford, an engineer of that town, his first wife having died in childbirth within two years from the date of their marriage.

To wind up the accounts, all the ornamental ware in stock was sold by auction at Christie's: the sale lasted twelve days.