Where Love Illumines — Donna Fletcher Crow

Mary Tudway is forced to choose between two worlds: the pleasurable life of her high society friends Sarah Child, heiress of Osterley Park, and the Bishop of Raphoe and his dashing Nephew, Roger; or the life of faith and service represented by the Countess of Huntingdon, her lovely daughter Selina and the witty but devout Rowland Hill.
The story moves through the fashionable worlds of London and Bath as the death of one friend, the elopement of another and the startling unveiling of the Highwayman of Hampstead Heath play their parts in Mary's finally making a choice of lasting value.