The Inspector Lynley Mysteries: Word of God
Also visible here : /vehicle_98598-Rover-75.html Enfield (india) Exotic Indian-made bike still made today,patterned on last UK-made(in late Fifties')original Royal Enfields(exists also diesel(!)fueled version in India,an indigenous project that exploits a Lombardini-license-made single-cylinder diesel engine)
Not a 350 Bullet but the 500cc. Can be seen by the protruding cooling fins located where the silencer meet the cylinder head.