Complex sentence: During a film-acting career that lasted from the early 1960s until 1975, she appeared in about thirty movies and was at one point under consideration as a replacement for Diana Rigg in "The Avengers".
Split into simpler sentences: During a film-acting career that lasted from the early 1960s until 1975, she appeared in about thirty movies. She was also considered as a replacement for Diana Rigg in "The Avengers".