Complex sentence: His first professional engagements were as a guitarist and cellist, playing with the Boyd Neel Orchestra, and in 1950, he made his first of many recordings with Alfred Deller, accompanying him on the guitar.
Split into simpler sentences: His first professional engagements were as a guitarist and cellist, playing with the Boyd Neel Orchestra. In 1950, he made his first of many recordings with Alfred Deller, accompanying him on the guitar.