Exhibit 10.15 ELEVENTH AMENDMENT AND CONSENT TO THE HOLDINGS GUARANTY ELEVENTH AMENDMENT AND CONSENT TO THE HOLDINGS GUARANTY (the "Eleventh Amendment"), dated as of April 16, 2003, among TRENWICK GROUP LTD., a company organized under the laws of...Holdings Guaranty • May 15th, 2003 • Lasalle Re Holdings LTD • Fire, marine & casualty insurance • New York
