Possible Clues:

• Awfully smart person fine about overcoming new barrier
• Hill State's boring for awfully clever chap
• One's unlikely to pass close to park which Berlin's had for over twenty years
• Wise guy providing king with zero security
• Smart Alec
• Self-styled polymath
• Walking encyclopaedia?
• Smart Aleck and Kelvin -- unlike Hadrian?
• Sounds as if nothing's been built, yet he'll tell you everything about it