In 1979 Westcott formed Security Design Electronics Ltd and took the Protec name with him. Successes were scored in the Far East and Saudi Arabia, as well as UK nuclear power stations, airports, prisons, and UK Royal and VIP residences including Chequers. SDA Protec became involved in the access control market, and also did work for the MoD. Westcott formed Falcon Protec to handle the military part of the business.
IES acquired the SDA Protec business, with Westcott remaining a major shareholder. His health began to suffer, although he continued to take an active part in the business. In 2005, the business was acquired by Quadnetics Group, and he joined the board as a non-executive director until he retired.