Every Duke Has His Thorn by Angelina Jameson

A duke and a budding architect…

Nicholas Barton, Duke of Preston, leaves England after the death of his mother, an overbearing woman who attempted to control the activities of her only child. He returns to England three years later, and after a disastrous month spent in London avoiding matchmaking mamas, the duke departs for his ancestral home, Barton Hall, in Lancashire. He finds the house rundown and the estate in shambles.
Miss Marina Davies, daughter of renowned architect Sir Joseph Davies, has no time for the aristocracy. Her deceased mother was the daughter of an earl, cast off when she married a mere mister. Content to assist her father in refurbishing great houses, Marina isn’t looking for romance, especially with a proud duke who left his responsibilities behind to travel the world.
Thrown together over several weeks while solving clues to a mythical treasure, Marina comes to view the duke as a kindred spirit rather than an enemy, and Nicholas begins to realize that the outspoken young woman he’d seen as a thorn in his side is now the woman he wants as his wife.