Just found this reported evidence, which would invalidate my assumption:
"Earlier the trial heard that James Denham and his brother William were passengers in a car travelling immediately behind Mrs Griffith's Peugeot.
The jury was shown a video of an interview with James Denham, who was 16 at the time.
He said: "As we were coming downhill, the car in front of us indicated right.
"Dad saw this and braked, but the car behind us went to overtake. It made contact with the car in front, which was half in the road."
The overtaking driver might even have been aware of the manoeuvre but incorrectly assumed that the turning vehicle would be sufficiently clear of the road.
"Earlier the trial heard that James Denham and his brother William were passengers in a car travelling immediately behind Mrs Griffith's Peugeot.
The jury was shown a video of an interview with James Denham, who was 16 at the time.
He said: "As we were coming downhill, the car in front of us indicated right.
"Dad saw this and braked, but the car behind us went to overtake. It made contact with the car in front, which was half in the road."
The overtaking driver might even have been aware of the manoeuvre but incorrectly assumed that the turning vehicle would be sufficiently clear of the road.