There are two different tunes called Pentonville.

Pentonville by Francis Linley is a hymn tune used for the hymn Like Sheep We Went Astray. It is in the Hymnary.

Pentonville by William Marsh of Canterbury is one of the popular settings of While Shepherds Watched. It doesn't seem to be in the Hymnary.

Lyngham by Thomas Jarman of Clipston is another popular setting of While Shepherds Watched. It is in the Hymnary.

Cranbrook by Thomas Clark of Canterbury is a further setting of While Shepherds Watched. Thomas Clark was a friend of William Marsh, and his tune is better known as On Ilkla Moor Baht 'At.