I have about six hours and wondering best thing to do with three children , 18,13, 10. I will be dropped by harrods. Wondering if to do the eye. Or the new emirates cable car, or covent garden. Don't want to spend loads . I am worrying how I would get to the cable car from Waterloo? I'm not very good with finding my way about! I wondered if to try to get the cable car and go to the cutty sark. Any recommendations would be great please! Thanks