Complex sentence: Unknown to director Mary Ridge, Gareth Thomas, determined to eliminate any ambiguity over Blake's death, had arranged with the visual effects team to ensure that there was as much blood as possible was seen when Blake was killed.
Split into simpler sentences: Unknown to director Mary Ridge, Gareth Thomas was determined to eliminate any ambiguity over Blake's death. He had arranged with the visual effects team to ensure that as much blood as possible was seen when Blake was killed.