Complex sentence: He stayed with the project when Olympia & York went into administration in 1991 working as Construction Director and then becoming Deputy Chief executive of the Canary Wharf Group when it was formed in 1995 and Chief Executive in March 1997.
Split into simpler sentences: He stayed with the project when Olympia & York went into administration in 1991, working as Construction Director. He became Deputy Chief executive of the Canary Wharf Group when it was formed in 1995, and Chief Executive in March 1997.