Complex sentence: Strickson is now an accumplished documentary producer and director, especially of wildlife programmes, having produced programmes for, amongst others, the Discovery Channel, the BBC, ITV, Channel 4, and Animal Planet.
Split into simpler sentences: Strickson is now an accumplished documentary producer and director, especially of wildlife programmes. He has produced programmes for, amongst others, the Discovery Channel, the BBC, ITV, Channel 4, and Animal Planet.