Complex sentence: Mathewson, who remained a keen rugby player until well into his 50s, took the role of the enlarged RBS group's executive deputy chairman and became chairman after the retirement of former Tory politician Lord George Younger.
Split into simpler sentences: Mathewson, who remained a keen rugby player until well into his 50s, became executive deputy chairman of the enlarged RBS Group. He became chairman following the retirement of former Tory politician Lord George Younger.