Possible Clues:

• Security device for motorcycle triallist
• Perhaps motorcyclist's security device
• Get lost, approaching centre of Dublin on flipping motorbike
• It clambers off road to begin with?
• Phone tap foiler
• Biker initially seen cycling ahead of walker
• Phone security device
• Security device ultimately saves frantic walker
• In dons' room fitter installs minute security device
• Reason for bad reception of person cooking eggs