Brotherly Love by Elizabeth Pewsey
Mimi, a purveyor of fountains (some a little too spicy for public parks) is married to Edmund Mountjoy, a historian whose book on the Templars has stalled. When Mimi s mother decamps abroad leaving no forwarding address, escaping her three grown-up sons who refuse to leave home, the sons descend on their sister - with extremely disruptive results. Driven mad by the brothers, Mimi and Edmund also flee, to France. But hot on their heels come Edmund s ex-mistress, the three tenacious brothers and a ghostly presence with its own singular perspective on Edmund s book.