At cricket, Barnwell was a middle-order right-handed batsman and an occasional right-arm medium-pace bowler. After captaining the first XI at Repton in 1963, he played four times for Cambridge University in 1965 and 1966 without gaining a regular place, and six times for Somerset in 1967 and 1968.
At cricket, Barnwell was a middle-order right-handed batsman and an occasional right-arm medium-pace bowler. After leading the first XI at Repton in 1963, he played four times for Cambridge University in 1965 and 1966 without securing a regular spot, and six times for Somerset in 1967 and 1968.