Bus rids in London provide ample photo ops, you should just hop on the 12 bus from Piccadilly and skip the over priced tourist buses. (12 goes through Piccadilly, Trafalgar square, Westminster, and it goes across Westminster bridge which gives you a good view of the London eye) You could always get off the bus at Westminster bridge and walk to the eye? Just a suggestion to save people like £10+ (bus ride without a oyster card is about £2.40)
