Possible Clues:

• Maybe I'm _____, 1970 Paul McCartney song
• Stunned a mother with last letter?
• A complex system observed before Durham's opener bowled over
• Piece of publicity about Long Kesh caused astonishment
• Agog
• Greatly surprised, astonished
• Knocked for a loop
• A child finally gets round labyrinth full of wonder
• ... floored by tangle inside plug
• Very surprised these days to go round part of Hampton Court gardens