THE richest MP in federal parliament, Malcolm Turnbull, and his wife, Lucy, have listed an $18 million-plus Point Piper harbourfront investment property. The house, designed by Michael Suttor and completed in 2003, is adjacent to the couple's $50 million residence. The marketing of the townhouse-style three-bedroom house has begun with an inspection from the merchant banker Mark Burrows. The three-level house has 400 square metres of living space.