Possible Clues:

• British composer's "London Bridge"
• Big name in book sales
• Sir - Wallis, World War Two bouncing bomb inventor
• __ & Noble
• Part of our capital in farm buildings, say
• - Wallis, British engineer (WWTwo bouncing bombs)
• Book chain co-founder
• The 'B' of B&N
• Prevents going around NE area of London
• Critic Clive