This property in Rue du Poivre, St John, gets no more than a passing mention in the first volume of Joan Stevens' Old Jersey Houses.
It is somewhat surprising that it figures at all, because the house, previously called Longchamp, was built in 1822, well after the cut-off point for the book at the end of the 17th century.
Perhaps it is the unusual 1680 datestone on an outbuilding which persuaded the author to mention the house, because it is inscribed 1680 IEL. That's unusual, because nobody has been able to attribute the EL part of the stone, which represents a surname, to any known name in 17th century Jersey. The stone has been hidden since the book was published in 1965.