Hi. We are a family of 7 ( 2 adults and 5 children ages : 10,14,15,18,20) We will arrive to London from my country on the 22 of Oct. 2009. I am confused which travel card to purchase : London Pass with Travel or Oyster card or Marlin annual card or any other card .... ? Do I need to purchase all of them to save money for the family ? appreciate your help . Talal