Complex sentence: After completing the fifth and final series of "The Professionals" in 1981, Collins struggled to find work, possibly because of typecasting: he found himself cast in macho, hard-man roles in foreign films.
Split into simpler sentences: After completing the fifth and final series of "The Professionals" in 1981, Collins struggled to find work because of typecasting. Thereafter he found himself cast in macho, hard-man roles in foreign films.