Possible Clues:

• Mine-field inspector, maybe
• Telegraph work it offers a circus a line
• Highly strung performer?
• One engaged in high-level risk taking while pursuing the straight and narrow
• His job's on the line!
• Daring balancer
• Circus performer
• My job is a balancing act, making progress while strung out
• Firm with secure Rover has high profile in circus
• My job's on the line -- it's over explosive Telegraph work