To be completely fair, this is totally standard practice in interviews, as many media organisations like to have 'their own' footage. There's a similar video of George Osborne, which also fails to annoy me.
It was a pooled interview so there was only one reporter and one camera present. Ed didn't repeat himself out of courtesy but repeated himself out of idiocy.
The reporter initially thought he was going to lose his job because he thought it was that bad an interview (link).